SourceTree for Windows appears to be forgetting the "extended integration settings" for repositories' remotes. I'm not sure if it affects all "host types", but my organization uses Stash, and it seems to reset itself not long after being set. I started noticing this ever since version 2.3 of the client shipped-- at least on my machine. Prior to version 2.3, I never had any issues with this feature.
From what I can tell, the settings don't get lost immediately, but usually after a day or so of using the client. I haven't been able to pinpoint what exactly causes them to be erased.