Reporting again because of deleted 2 reports before.
Isusue doesnt hapen on 1.14.4.
Please take notice this is vanilla. Take a look = integrated server. World is made with vanila minecraft and used only in vanila minecraft.
https://youtu.be/ZABMmFLuDbA

UPDATE:

1. Added debug of area in video with lag and without lag.
The diference is in laggy blocks geting moved.
profile-results-2020-01-23_02.58.32.txt = laggy
profile-results-2020-01-23_03.07.33.txt = no lag
2. Lags when chorus is growing.
3. Lags when blocks geting broken.

Poor render/lighting engine performance making client lag.
Most likely lighting resets in whole chunk!
This isusue have something to do with skylight.

Here another video playing with it.
https://www.youtube.com/watch?v=q4ZkJIkclN0