Very interesting. I found it odd that when I happened to open IG yesterday, I was prompted to log in, and my password didn't work. I asked it to send me a link to my email and got in that way, and didn't have time to look into it further.

So I went to check it again just now after reading your comment, and I was immediately as soon as I opened the app, prompted to create a new password, which I did.

very very sketchy things going on here. But I'm glad that they didn't fully allow my account to be stolen :/