I have no way to check if this problem exists in the vanilla server jar but i noticed a large increase in overworld chunks after our server updated to 1.14.2 (have not checked the behavior of other worlds).

It "appears" that as players move around chunks are loaded/generated but not properly unloaded. The screen shots below show OVERWORLD stats (code snip below)

File ending in 03.png was taken just before everyone was kicked prior to a restart.

File ending in 17.png was taken after kickall, after a saveall, and before the restart. The overworld render distance is set to 4 and you can see that tons of chunks remain loaded which have no reason to be loaded.

File ending in 48.png was taken after the restart and 15 players re-joined into the overworld.

30 minutes uptime
14 players in overworld
9555 chunks loaded (render distance 4)
--All players kicked
--saveall run (saveall was completed before the screenshot - the saveall is run by an external script)
7339 chunks remain loaded
– server restarts
15 players in overworld
3667 chunks loaded (still feels high given a render distance of 4 and 15 players - but much more reasonable)

    World w = Bukkit.getWorld("world");
    Chunk[] chunks = w.getLoadedChunks();
    mobsScoreOverworldChunks.setScore(chunks.length);