In 1.14.4 you can see all chunks updates but in 1.15 they are not displayed
MC-166832
"chunk updates" in F3 no longer works
Resolved
Won't Fix
1
I've had this issue in 1.15 Pre Release 4, HOW TO REPRODUCE: Choose 1.15 Minecraft installation, open world, go/open F3 (coordinates & info).
I tried it out on a superflat world, maybe it works in a normal world. I just wanted to say that I also experienced it. Hope it gets resolved soon!