I'm not sure why but absorption doesnt seem to have a cooldown, applies instantly, and stacks infinitely.

Screenshot shows things off the block and doesnt seem to go away despite logging out

Wow, I tested in 1.19.2, 1.19.4 & 1.20.1 and I couldn't reproduce this.
What version of minecraft/mod are you using?

1.20.1
Heres the instance I'm using. Click and drag it into MultiMC and it will recreate it with my configs.
Its not giving me any errors server side.
https://drive.google.com/file/d/16NJS50Nf5denIUtaG3HPLWb7np7SmZEe/view?usp=sharing

Indeed, I think there's a compatibility issue with a mod that accumulates absorption effects. It also does it when you eat a golden apple.
However, I've searched and can't help you figure out which one, sorry..

it would be easy if there was a log of some kind but oh well. Thanks.

I persevered and found it!
The mod is Big Extra.

oh thank god. I was running through configs and not finding it. Is there a fix I can implement?

I don't know, I haven't even seen a config option mentioning this behavior. I recommend you to report the bug on the mod page :
https://github.com/shiftthedev/BigExtras/issues

sounds good. Thank you so much.