Good day,
we have a problem with the dynmap.
Our card was completely black after the world border.
Gradually, however, more and more individual chunks are sporadically uncovered. Without that there was a user. There are already 22 chunks that have been rendered.

Keep in mind if someone uses the /locate command it will cause the game to randomly "sample" map chunks looking for the requested structure, resulting in a similarly dotted generation. I personally haven't noticed Dynmap generating any new chunks on any of my maps (Multiverse server), and I've been using it for a few years now.

Dynmap never 'makes' chunks - it renders what is there. MC will make chunks, particularly due to things like structures/mines/etc, that will exist beyond movement borders implemented by WB or the like. If WB doesn't prevent these from being created, that isn't a dynmap problem - we only render what exists. If you configure visibility limits for the given world (in the dynmap config for the world - see the 'dmap' command - specifically the worldaddlimit, worldgetlimits and worldremovelimit subcommands - to define the map 'clipping' to dynmap explicity), we'll use those to ignore chunks outside the intended visible area. Dynmap doesn't support WorldBorder - WorldBorder just supports dynmap enough to tell us to draw a circle or square.