Hi @buttersflg,
thanks a lot for the detailed updates, and good that you found a solution. You actually found a bug, which I documented in an issue: Wrong order of writing data · Issue #27 · precice/code_aster-adapter · GitHub
We have noone working on the code_aster adapter since a while, and it was always something extra that we needed to maintain, but could not easily test. If your work depends on this adapter, we would very much appreciate some help to keep it up-to-date and fix such issues.
The issue I opened now is very easy to contribute a fix for (and you already identified the fix). If you want, go ahead an open a pull request, otherwise I will add the fix later.
By the way, last time I checked, I had trouble installing code_aster 14.6 on newer systems (the release was from 2020, and code_aster 15 seems to be in testing mode since a long time). Do you maybe know what the status of code_aster is at the moment?