In 1.20.1 when I first come across newly loaded chunks with burrows I can right-click to examine them and it produces a chat message, which I assume is an indicator that they're functional and will spawn critters - because they do, they still work like this.

After leaving the area and returning back to those chunks it is no longer possible to right-click the burrow, and it appears as if no critters ever end up spawning from them.

EDIT: Seems specifically to be connected to chunks being loaded or not, since using a chunkloader on the location of burrows stops this issue. However... having one loaded chunk, seems to solve the problem for burrows up to several chunks away? I have no idea what could be happening.

EDIT2: Leaving and rejoining the world causes this behavior to happen despite chunkloaders being used (likely a problem with the chunkloaders, though)

I too am experiencing this. they function as normal when i first load in a chunk. As soon as i log out/leave and come back they no longer do/say anything when i right click.

I am also having this issue.

I also experience this, with the server console stating this after I click a burrow from an already previously loaded chunk:

[Server thread/ERROR] [minecraft/PacketUtils]: Failed to handle packet net.minecraft.network.protocol.game.ServerboundUseItemOnPacket@1dbe155a, suppressing error
java.lang.NullPointerException: Cannot invoke "net.minecraft.world.entity.EntityType.m_20676_()" because the return value of "untamedwilds.block.blockentity.CritterBurrowBlockEntity.getEntityType()" is null