I am not quite what mod this falls on, but here is the issue:

After repositioning StatusEffects to be next to my hotbar, Seamless loading screen now displays my status effects as of logging out in a really odd location:

you apparently just need to check options.hudHidden before renering stuff to fix this.

Vanilla minecraft doesn't disable the status effects when the HUD is hidden in certain cases (atleast from my glance at the code), so it shows up here. I don't really want to change vanilla functionality, but if you really feel that it's a bug I can force it to check before it renders.