Ah, I can sympathize with your situation!
If it’s any consolation, the “normal” software cannot be rolled back either - there’s a two week (or so) period of overlap and after that you need to update as well.
Back to topic:
I find it weird that it worked before since changing the ground plane was never intended to be a permanent transition - there is the button “Reset Ground” after all.
A workaround would be to transform your existing CPs into GCPs. Since they seem to be on the floor and you know the distance, you can establish their coordinates. Now create a third GCP on the floor, use the “is” coordinates and paste them into the “should” fields. In theory, you only need to hit “Update” to re-orient the model.