FB on ipad freezes on 'comments', navigation vanishes so I can't exit page

For the past few weeks, every time I click to open a comment on a post in the FB app, it opens the comments & asks me to leave a comment, but there is NO navigation at the top of the page & so no way to exit this page - can't even get back to the post itself, I'm stuck there. The only way to get away from that page is to close & re-open the app.

Does anyone have any idea how to get round this?

I'd love to know why Apple devices make very simple things stupidly complicated and messed up 🤦🏻