Navigation Bug

Navigation bug bringing misery. Sometimes I go into a patch, edit it, and try to go back to its parent patch and I get this error message that forces me to close the program.
I’m using preview 147, (but also goes back to 124).
Hard to explain exactly how to recreate it without my local setup, but maybe the devs can unpick it.
This doesn’t occur with Gamma 975
Navigation Bug.log (55.8 KB)