Head of subgridded drill easily stuck in terrain
When a drill sits on a subgrid, it is extremely easy to get its moving part stuck in terrain by running into it fast enough. Subsequent attempts to move can easily lead to ripping off the entire subgrid.
The magic minimum speed appears to be 25 m/s.
Happens to both large-grid and small-grid drills.
On non-subgridded drills, the function is normal: The grid stays intact and instead punches a sizeable hole into the voxel.
Observed on single-player, local world. It's possibly the same, or worse, in multiplayer, especially so on a remote server.
Note: This looks like it's what happened in https://support.keenswh.com/spaceengineers/pc/topic/24704-new-small-adwanced-rotor-head-blows-up-large-rotor.
Video and ship blueprint attached.