You're on lemmy.world which is still using v0.17 and the new jerboa version requires v0.18 to fully work.
lemmy.world will be updating when v0.18.1 gets released so for the time being revert back to jerboa 0.0.34/33. It'll crash every time you launch so turn on airplane mode, go to the login menu and only then turn airplane mode off and click log in
There are a couple bugs for this already, and it seems to happen when your network is unstable or your instance is under load. If it seems random, it's probably just a crash when the hung network request to your server finally errors out.
If you notice any immediate crashes (i.e. you do X then it crashes immediately), please note those.