Yeah it goes back in place and fits perfectly once i push it back into place. I’ll go the glue and nail route. Thanks!

I tend to lean towards it being humidity since we have only noticed it happened in the last couple of weeks where temperatures in this area are higher than normal, humid and our AC has not been working for months (just had it repaired today).

Awesome, did more digging and it turns out it’s an HRV and likely not something I need to be running during the summer months as I don’t need more warm air circulating and we keep windows open often enough to naturally exchange the air.