The lemmy.world instance was just updated to version 0.18.2. The login issues
that were being reported (for example, here [https://lemmy.world/post/1364490])
are now resolved. For release notes: https://lemmy.world/post/1339018
[https://lemmy.world/post/1339018]
Had the same issue, hopefully this is the last time I have to sign in again for a while 😅