The best thing we can do here is provide useful feedback on what isn’t working and the steps needed to reproduce the errors or issues.
As a development manager and architect I fully understand what is required to identify and fix bugs in software. Comments like most of those here are not useful. yes we are frustrated when things are not working, but unless those issues can be reliably reproduced, there is little or no chance of fixing them.
For the moment, we do know that issues with undo occur, but specifics about when and how are largely unknown. let’s all work together to get that missing information, We need to get steps that will cause the issues every or nearly every time.
Then, and only then, can a fix be planned, designed and coded.