Chunks loading but not rendering

[Cota]

This is a bug but i see no pint in "reporting it" since it has been done.

This is research, since searching for a fix only takes you to the obvious answers like: "increase the memory", "re-download" and things like that.

Thing that i know:

-Its a server thing.

-Moving the map files to a new server setup, doesn't works.

-It comes and goes like a ninja.

-Chunks do download but are not rendered, they appear on the mini map.

-Non lag related.

So the golden question is: any one knows anything else?

Screenshots:

Sky Vision

Bedrock Vision