Is there a safe app to see who unfollowed me, or do those all steal your login?

Rule of thumb: any app asking for your Instagram PASSWORD directly is a hard no, that's exactly how accounts get hijacked and added to spam-follow botnets. Even the ones using official login tend to get your account flagged for 'suspicious third-party access'. The safest method is honestly manual, or just letting it go. Your account security is worth more than the data.

Following, been wondering the exact same thing.

Same issue here after the last update. The fix above sorted it.

Same here, glad someone finally asked this one.

I used one of those apps years ago and got my account temporarily locked for 'suspicious activity' the next week. Never again. Not worth it.

Adding to the accepted answer: results vary a bit by phone and OS version.

Solved the same thing by switching between wifi and mobile data, oddly enough.

For what it is worth, this behaves differently on iPhone vs Android in my experience.

This thread is really useful, bookmarking it.

Great question. Half my contacts have hit this and never knew the fix.

This is exactly why I read the forum before touching settings, thanks all.