There is already code that prevents two or more instances of the same profile running at once in two or more instances of the program (or even in the same instance of the program). Or, the converse - code that prevents two or more instances of the program trying to run the same profile (however you prefer to visualize it). But that's not the issue.
(The only thing we can think of is that maybe...) a profile is running in one instance (at least, that something has a lock on the INI file of that profile: there's no proof what process that is) while the instance of the program that (maybe) kicks out the profile does so during the load-up cross-check process on start-up (way before it starts thinking about actually running any profiles), because the cross-check between a group membership entry in the group INI hits a lock on the INI for the actual profile).
But no-one else is reporting any such issue, so we're only theorizing. Could be a different process altogether locking the profile INI.
(The only thing we can think of is that maybe...) a profile is running in one instance (at least, that something has a lock on the INI file of that profile: there's no proof what process that is) while the instance of the program that (maybe) kicks out the profile does so during the load-up cross-check process on start-up (way before it starts thinking about actually running any profiles), because the cross-check between a group membership entry in the group INI hits a lock on the INI for the actual profile).
But no-one else is reporting any such issue, so we're only theorizing. Could be a different process altogether locking the profile INI.