FATAL: Unrecognized Instruction (Signal 4 / SIGILL) when joining any experience on x86-64-v2 CPU

### Carefully follow the checklist to get started with the bug report - [x] I have checked if my issue has already been reported, and I am certain that my problem has not already been addressed. - [x] I agree to explain the bug exactly as-is, without using any AI-generated summaries or explanations. - [ ] I agree that I just checked every box without actually reading anything. ### In your own words, briefly explain what went wrong I expected to play normally, but the client closes when trying to join any experience with a **Unrecognized Instruction**. Sometimes after using `flatpak repair` I can see the game loading, but it shows **Unknown status** at the bottom of the screen and then any experience again crashes Sober. Sober: 1.7.1 (b48714c7c58640269e11c15726675c61346a2f697f66ff30388eddd74da39717) CPU: Intel Core i5-4690K (SSE3: Yes; SSSE3: Yes; SSE4.1: Yes; SSE4.2: Yes; POPCNT: Yes; AVX: Yes) Crash output (captured from the terminal, as it was absent in latest.txt): ```text info: app_interface$json: {"type":"will_handle_start_game"} info: Roblox: 2026-08-17T22:00:03.571Z,149.571442,cc8ec4c0,6,Info [FLog::JNIAppBridge] nativeAppBridgeV2StartGameWithParam: --------------------------------------------------------- FATAL: Unrecognized Instruction --------------------------------------------------------- Received signal: 4 (Illegal Instruction) Faulting RIP: 0x7f27ca179db7 Instruction Bytes: [f, b, bf, e, 0, 0, 0, be] This program requires a CPU with x86-64-v2 features. We attempted to emulate missing features, but encountered an instruction that could not be handled. Printing CPU info: CPU Vendor: GenuineIntel CPU Brand: Intel(R) Core(TM) i5-4690K CPU @ 3.50GHz CPU Feature Support: SSE3: Yes SSSE3: Yes SSE4.1: Yes SSE4.2: Yes POPCNT: Yes AVX: Yes While your CPU supports SSE 4.1, illegal instruction errors can also be thrown due to the program encountering something it didn't expect as a way to quickly stop itself. Check your configuration, verify file integrity, and try again. If nothing works, you should probably report this as a bug. ``` ### How could someone else run into the same bug? Provide anything relevant: when the bug started happening, how to get it to happen, etc. 1. Launch Sober on Arch Linux (KDE Wayland session) 2. Try to join any experience I have noticed the bug at the evening of 17.08.26 (dd/mm/yy) around 20:30 UTC. That's also a day after I copied my system to another SSD using `dd`, but I have seen some other issues(like #2436 or #2437) that in my opinion a bit similar to my problem, so I don't think that's the reason what caused the bug. I haven't done anything to cause the bug like updating Sober, updating flatpak, etc. ### Attach Sober diagnostic logs [latest.txt](https://github.com/user-attachments/files/31156310/latest.txt) ### Upload screenshots [Screencast_20260818_000001.webm](https://github.com/user-attachments/assets/43985bd2-f463-423e-b7b3-3200324a4ba1) ### Roblox Experience link _No response_