The nightvision given by the bat backpack has a strobing effect. I believe it has something to do with how you are re-applying the potion effect, and I think Botania solved a similar problem with its Ring of Chordata a while back. It might have been a different mod with a different item ;x.

Thanks.
To tell the truth, it doesn't happen in my system, but I'll check it out shortly.

Succesfully replicated, looking for solution.

Still working on a simple way to make this work... but maybe "simple" is not a realistic goal.

Fixed for next version 🎯