Worldboarder makes player sufficated in Walls

When starting to decrease worldborder (like 300), then changed to survival, and player gets damage from somewhere. No walls are nearby. Inside a world boarder. But are I starting to get suffocate when I'm not get nearby to boarder. Also, effects on mobs. Every mob gets sufficating. Somehow, my problem is weird. When Im on about 50 block before the border, I dont get any damage. Also for the mobs.