Version login bug

Put the summary of the bug you're having here

What I expected to happen was...:
I would load my survival world and play.

What actually happened was...:
Constant lag, 1 frame every few seconds. Switching to 1.14.4 fixes it, but no 1.14.3 play.

Steps to Reproduce:
1. Make a 1.14.3 world 
2. Try to play 
3. Examine