This is not normal.
If a factory didn’t fix it you can go one step further to exclude the OS gone bad as a reason.
If you have the official Facebook App installed, you could uninstall it to see whether it has gone rogue (which it might do).
You could try whether the issue persists if you remove your SIM card(s) from the phone. Especially SIM cards getting old sometimes cause trouble which you wouldn’t attribute to them logically.
If you incorporated an SD card into Internal Storage instead of keeping it as external storage … don’t do that, it’s inviting trouble. SD cards are pretty flimsy and when (rather than if) they go corrupt, they will hamper phone operation or corrupt the whole Internal Storage.
In the end this needs fixing. If nothing here in the forum helps, you should contact Fairphone support … https://support.fairphone.com/hc/en-us.