Label Is not very clear

I used different version with cesium

letf one is 1.11 , right one is 1.9
The following rendering:

the effect of older verison is better than newer version.

i only added property of backgroundcolor. I think this will not affect the effect.

the two version used the same code to add entity

I am sorry . I made a mistake

letf one is 1.09 , right one is 1.11.

sorry .

This is a known issue due to renderer changes for vector data on terrain. Keep your eye on, which will eventually get merged into master.