Trussed slicksters are phased into natural tiles when wrangled on an oil covered slope.

When a slickster is auto-wrangled at a critter droppoff that is located on stepped natural tiles, covered in oil, the trussed critter will be forced into the tile, getting entombed.
This was encountered while setting up a dirty brick slickster ranch while trying to relocate slicksters from one ranch to another.

Steps to Reproduce

Place a critter drop-off on a stepped abyssalite staircase covered in oil with slicksters nearby
Set the critter droppoff to autowrangle surplus with a limit of less than the currently held ranch
Rancher will wrangle a slickster
The newly trussed slickster will appear in the tile of the dropoff station for a brief moment before phasing into the tile to the right.
Trussed slickster is now entombed in a natural tile.