Describe the bug

First cast appears with (Uknown) instead of (1).

Do you have an error log of what happened?

No

Did you try having DeadlyBossMods as the only enabled addon and everything else (especially something like ElvUI) disabled?
No

Which version of DeadlyBossMods are you using?
30af280

Was it working in a previous version? If yes, which was the last good one?
Dunno