Since I think ~IDA 7 there seems to be a very annoying issue with changing function stack pointers/register/variable settings.
They basically often auto reset after changing. This makes analysis and working with functions that have wrong detected settings very hard.
The last time this worked was in IDA 6.8 as far as I know. Maybe this can still be addressed in the upcoming IDA release.
I am talking about the settings in the following screenshot:
