I've been fighting this problem for a while now & have finally reached the breaking point. In almost every flow simulation that I've run, I'll constantly run into issues where defined features "forget" the faces that I've assigned.

I can understand this happening if I'm changing model geometry that specifically pertains to said feature, but when it happens to a face/feature that I haven't touched (& pretty much happens all the way down the model tree), this can be aggrivating, especially when I have a 10+ hour run that finishes only to realize that certain critical faces have lost their definition (e.g. an outer shell losing it's radiative surface when running a solar loading analysis), which pretty much invalidates my entire run.

Occasionally I'll just save/close the part, open it back up & everything appears to have fixed itself. But as I mentioned earlier, sometimes this is missed before a run starts & then hours of simulation/solving time are wasted.

Is this a known bug and/or is there a seemingly simple fix?