After doing a fresh bundle build from master, I went in and set my UI:Settings capability not to timeout (Session timeout = 0) and saved.
After I clicked to access Atlassian Crowd and received the popout to discard or go back.
I clicked go back, saved again and tried to navigate away again no dice.
If you discard, this works and does not occur a second time. NOTE: The changes DO save despite clicking discard. However, also note/clarify, if you make new changes on leave then return this occurs again. Browser refresh/restart is not required to see this a second time.
I feel like this is recent behavior because this is something I do almost every build. Despite this, I did not back check older NX3 (or NX2) at this time so am not 100% sure.
I do also feel like issues like this have been intermittantly popping up, however, on search I did not see one like this.
Let me know if you need a vid, should be pretty easy to get.
I tried this with debug on (and off), no errors in JS or nexus log.