I'm not sure if we paid for the cape again, I don't remember exactly. So, we didn't need to repeat the quest, but we just had to follow the steps like (maybe) paying for the cape and registering the symbol again, and then everything was good. Now all fine.

Clovis was kind enough to test it real quick, it seems that the debuffs are stacking up to NPCs. Anyways, problem has been addressed and will be fixed on next restart.

this seems like an official bug, since your clan was downgraded it also means that you're no longer promoted so you shouldn't have a cape nor a symbol and would need to complete the caitharos quest again. but it seems that clan leader being online somehow breaks the update. sadly there's not much information about it yet.

We didn't redo the Caitharos quest; we simply added characters with NP to the clan and grade increased automatically as normal. The cape was automatically granted, and the symbol returned to the cape automatically, but the symbol did not appear next to the character nicknames. We didn’t re-register the symbol since it was already on the cape. But now we re-registered this and now its fixed, appearing next to nickname and on the cape correctly. Thanks for support.

Yes, all damages appear to be normal, and the Bifrost Monument is once again unkillable without 6-7 parties, as it was before.