Hi when roaming the world I get 5-15s hangs that freeze client (im in single player world) and my logs point to only one thing happening each time:

[11Jan2021 10:57:59.905] [Server thread/WARN] [net.minecraft.world.server.ServerWorld/]: Trying to add entity with duplicated UUID 0e0f80a6-5ee1-4b42-a8a3-49ea7243b1b9. Existing minecraft:chest_minecart#93896, new: minecraft:chest_minecart#95202
[11Jan2021 10:58:08.654] [Worker-Main-27/WARN] [TerraForged/]: Feature was slow to generate! (8131ms): [bettercaves:bettercaves]
[11Jan2021 10:58:08.691] [Server thread/WARN] [net.minecraft.world.server.ServerWorld/]: Trying to add entity with duplicated UUID 41058cf1-b5f1-423c-b272-d73c977aae82. Existing minecraft:chest_minecart#92477, new: minecraft:chest_minecart#95258
[11Jan2021 10:58:08.713] [Server thread/WARN] [net.minecraft.server.MinecraftServer/]: Can't keep up! Is the server overloaded? Running 8150ms or 163 ticks behind

Potential duplicate of #76

Closing this as it also seems to have been dungeoncrawl as another issue was