Realm-Swift crash in `Array::get_context_flag_from_header` after updating to iOS 26.2

#### SDK and version SDK : Realm Swift Version: 10.54.6 (also occurs on 10.32.0) #### Observations * How frequent do the crash occur? Anytime I try and init a Realm database. * Does it happen in production or during dev/test? Prod * Can the crash be reproduced by you? Yes * Can you provide instructions for how we can reproduce it? It seems like running on iOS 26.2 is when this started to show up. #### Crash log / stacktrace ``` /Users/runner/work/realm-swift/realm-swift/core/src/realm/index_string.hpp:293: [realm-core-14.14.0] Assertion failed: Array::get_context_flag_from_header(alloc.translate(ref)) with (ref, size_t(alloc.translate(ref))) = [1677384, 4511160392] 0 Realm 0x00000001053f40ac _ZN5realm4utilL18terminate_internalERNSt3__118basic_stringstreamIcNS1_11char_traitsIcEENS1_9allocatorIcEEEE + 32 1 Realm 0x00000001053f4024 _ZN5realm4util19terminate_with_infoEPKcS2_lS2_OSt16initializer_listINS0_9PrintableEE + 396 2 Realm 0x00000001052bbf10 _ZN5realm11GroupWriter29move_free_in_file_to_size_mapERKNSt3__16vectorINS0_14FreeSpaceEntryENS1_9allocatorIS3_EEEERNS1_8multimapImmNS1_4lessImEENS4_INS1_4pairIKmmEEEEEE + 0 3 Realm 0x00000001052c877c _ZN5realm11StringIndexC1EmPNS_11ArrayParentEmRKNS_13ClusterColumnERNS_9AllocatorE + 356 4 Realm 0x00000001053b1a60 _ZN5realm5Table23refresh_index_accessorsEv + 508 5 Realm 0x00000001052b4584 _ZN5realm5Group21create_table_accessorEm + 900 6 Realm 0x00000001052b41a8 _ZN5realm5Group12do_get_tableEm + 120 7 Realm 0x00000001053cf270 _ZN5realm11Transaction19upgrade_file_formatEi + 860 8 Realm 0x0000000105294f68 _ZN5realm2DB19upgrade_file_formatEbiii + 280 9 Realm 0x00000001052934f4 _ZN5realm2DB4openERKNSt3__112basic_stringIcNS1_11char_traitsIcEENS1_9allocatorIcEEEERKNS_9DBOptionsE + 5200 10 Realm 0x000000010529a358 _ZN5realm2DB6createENSt3__110unique_ptrINS_11ReplicationENS1_14default_deleteIS3_EEEERKNS1_12basic_stringIcNS1_11char_traitsIcEENS1_9allocatorIcEEEERKNS_9DBOptionsE + 164 11 Realm 0x00000001054ea8e4 _ZN5realm5_impl16RealmCoordinator7open_dbEv + 1012 12 Realm 0x00000001054eb628 _ZN5realm5_impl16RealmCoordinator12do_get_realmEONS_11RealmConfigERNSt3__110shared_ptrINS_5RealmEEENS4_8optionalINS_9VersionIDEEERNS_4util17CheckedUniqueLockEb + 76 13 Realm 0x00000001054eb544 _ZN5realm5_impl16RealmCoordinator9get_realmENS_11RealmConfigENSt3__18optionalINS_9VersionIDEEE + 484 14 Realm 0x0000000105535094 _ZN5realm5Realm16get_shared_realmENS_11RealmConfigE + 120 15 Realm 0x00000001051bb568 +[RLMRealm realmWithConfiguration:confinedTo:error:] + 952 16 Realm 0x00000001051bb0ac +[RLMRealm realmWithConfiguration:queue:error:] + 156 17 RealmSwift 0x000000010413fe48 $sSo8RLMRealmC13configuration5queueABSo0A13ConfigurationC_So012OS_dispatch_C0CSgtKcfCTO + 152 18 RealmSwift 0x00000001041ed3d0 $s10RealmSwift0A0V13configuration5queueA2C13ConfigurationV_So012OS_dispatch_D0CSgtKcfC + 124 19 Crinkles.debug.dylib 0x00000001039ed7b0 $s8Crinkles13RealmProviderC5realm0B5Swift0B0VyF + 152 20 Crinkles.debug.dylib 0x000000010399f240 $s8Crinkles12VersionModelC07versionC033_C3780D180505F4AF68E859422EDF01B8LL3forACSgAC0B4TypeO_tFZ + 92 21 Crinkles.debug.dylib 0x000000010399f160 $s8Crinkles12VersionModelC7version3forSiSgAC0B4TypeO_tFZ + 48 22 Crinkles.debug.dylib 0x0000000103907a50 $s8Crinkles15ModelControllerC12brandVersionSiSgvg + 44 23 Crinkles.debug.dylib 0x0000000103907e68 $s8Crinkles15ModelControllerC10loadBrands33_99B6229989702B30755BD2CDC61F6CD4LL4fromSbSDySSypG_tKF + 368 24 Crinkles.debug.dylib 0x0000000103907bf4 $s8Crinkles15ModelControllerC15loadInitialDatayyFyyXEfU_ + 64 25 Crinkles.debug.dylib 0x0000000103908b1c $sIg_Ieg_TR + 20 26 Crinkles.debug.dylib 0x0000000103908b40 $sIeg_IyB_TR + 24 27 libdispatch.dylib 0x0000000103571d6c _dispatch_client_callout + 16 28 libdispatch.dylib 0x0000000103568e0c _dispatch_lane_barrier_sync_invoke_and_complete + 172 29 Crinkles.debug.dylib 0x0000000103907b48 $s8Crinkles15ModelControllerC15loadInitialDatayyF + 228 30 Crinkles.debug.dylib 0x00000001039eadfc $s8Crinkles15RootCoordinatorC9bootstrap16skippingDBUpdateySb_tF + 444 31 Crinkles.debug.dylib 0x0000000103957294 $s8Crinkles13SceneDelegateC5scene_13willConnectTo7optionsySo7UISceneC_So0I7SessionCSo0I17ConnectionOptionsCtF + 612 32 Crinkles.debug.dylib 0x0000000103957698 $s8Crinkles13SceneDelegateC5scene_13willConnectTo7optionsySo7UISceneC_So0I7SessionCSo0I17ConnectionOptionsCtFTo + 116 33 UIKitCore 0x000000019875b428 15414C36-D442-3F06-96CD-791887BE07FC + 259112 34 UIKitCore 0x00000001988632a0 15414C36-D442-3F06-96CD-791887BE07FC + 1340064 35 UIKitCore 0x0000000198858d30 15414C36-D442-3F06-96CD-791887BE07FC + 1297712 36 UIKitCore 0x0000000198863e58 15414C36-D442-3F06-96CD-791887BE07FC + 1343064 37 FrontBoardServices 0x00000001b3f42734 5949593B-27F4-3693-9310-5754D69E08AE + 153396 38 FrontBoardServices 0x00000001b3f3d8ac 5949593B-27F4-3693-9310-5754D69E08AE + 133292 39 FrontBoardServices 0x00000001b3f424d8 5949593B-27F4-3693-9310-5754D69E08AE + 152792 40 FrontBoardServices 0x00000001b3f41c0c 5949593B-27F4-3693-9310-5754D69E08AE + 150540 41 FrontBoardServices 0x00000001b3f415b0 5949593B-27F4-3693-9310-5754D69E08AE + 148912 42 FrontBoardServices 0x00000001b3f41928 5949593B-27F4-3693-9310-5754D69E08AE + 149800 43 FrontBoardServices 0x00000001b3f41724 5949593B-27F4-3693-9310-5754D69E08AE + 149284 44 FrontBoardServices 0x00000001b3f415b0 5949593B-27F4-3693-9310-5754D69E08AE + 148912 45 libdispatch.dylib 0x0000000103571d6c _dispatch_client_callout + 16 46 libdispatch.dylib 0x000000010355c4c0 _dispatch_block_invoke_direct + 296 47 BoardServices 0x00000001ab5a4f84 3D4773ED-61BF-3159-9081-D0564508FE7A + 180100 48 BoardServices 0x00000001ab5a4e00 3D4773ED-61BF-3159-9081-D0564508FE7A + 179712 49 CoreFoundation 0x0000000192c4adec B8C4A762-0973-3240-B782-850DB2A1FBB3 + 654828 50 CoreFoundation 0x0000000192c4ad60 B8C4A762-0973-3240-B782-850DB2A1FBB3 + 654688 51 CoreFoundation 0x0000000192c100ac B8C4A762-0973-3240-B782-850DB2A1FBB3 + 413868 52 CoreFoundation 0x0000000192bd9e30 B8C4A762-0973-3240-B782-850DB2A1FBB3 + 192048 53 CoreFoundation 0x0000000192bd91dc B8C4A762-0973-3240-B782-850DB2A1FBB3 + 188892 54 GraphicsServices 0x00000002394cb498 GSEventRunModal + 120 55 UIKitCore 0x000000019883cd18 15414C36-D442-3F06-96CD-791887BE07FC + 1183000 56 UIKitCore 0x00000001987a8068 UIApplicationMain + 332 57 Crinkles.debug.dylib 0x0000000103a01884 __debug_main_executable_dylib_entry_point + 64 58 dyld 0x000000018fae4e3c 1D1E19AC-4807-39F1-80FB-D27A4C2C61C0 + 20028 !!! IMPORTANT: Please report this at https://github.com/realm/realm-core/issues/new/choose ``` #### Steps & Code to Reproduce I can attach my database if that would be helpful.