Subscript out of bounds with multiple output equations

I suspect this is due to the regression line calculations. ### Discussed in https://github.com/LAPKB/Pmetrics/discussions/255 <div type='discussions-op-text'> ^{Originally posted by **BoburaII** March 27, 2025} Hi, I’m trying to plot `op` from a PM_result object (`res`), using: `res$op$plot(outeq = 2)` I get the error: `Error in summary(mod)$coefficients[2, 2] : subscript out of bounds` This didn’t happen previously with the same model and data. The model has 3 output equations, plotting op with `outeq = 1` or `outeq = 3` is fine. I'm using Pmetrics 2.1.1, R4.3.1, and recently updated macOS sequoia. I appreciate any help with this. Bob</div>