I encountered a bug where the effects of Branding, after being applied to the player through the lingering creeper explosion effect, persist even after the effect is not applied to the player. I have fire resistance and still take damage from fire even after branding is no longer applied to me. Player death is the only way I have found to reset the "shadow branding" effect.

Could you be more specific about this issue? Most notably which version of the mod you are using, as I am unable to reproduce this in 1.21 (in fact, Branding is broken there as well, but for an entirely different reason)

I'm on version 0.19.9 for 1.20.1. Basically, fire damage bypassing fire resistance due to branding, and potentially the increased fire damage, happens to my player even after the branding effect duration has finished. This was solved by killing my player, where I was then immune to fire again through fire resistance. I recreated this is a creative world to make sure it wasn't world-specific.