Forge. 2701
Mekanism 1.12.2-9.4.10.345

The digital miner changed to bounding blocks and can't be mined after that. I have to replace it in creative mode.

What? You mine it with a pickaxe or use a sneak-right-click with a wrench. You're showing with just a hand.

Hand and pickaxe did not work. The digital miner converted before I had tried to mine it. And this happens at the same postion again every time I place it there.

It does not "convert" to anything. A digital miner is a 3x3x3 multi block. 1 digital miner block, 8 bounding boxes.

If a pickaxe breaking it does not work then it is likely a server or other mod issue. Breaking a bounding box will break the main structure.

But normally it is shown as digital miner and not bounding block in WAILA. How can I find out which mod causes this behavior?

Remove mods until it no longer happens if you're sure that was the original behaviour.

Also be sure you're not actually using TOP, as it may do things differently.

That was HWYLA.

It always happens if a place it on blocks of Underground Biomes.