- Edited
I think this is a good indicator that it's always the default profile leaking into a secondary profile, never the other way around.
I can confirm it's always the primary profile storage leaking into other profiles. I've seen this problem off and on over the last few months.
Another note: you don't have to have the primary profile open and then load another profile. Loading the secondary profile from an application shortcut directly to that profile will sometimes trigger this as well. As will switching from a secondary profile to a third profile.
It's always the primary profile storage that leaks, though, regardless of which profile is opened and where it's opened from.