Striders cannot pathfind between lava and bottom slabs

Striders have trouble pathfinding between bottom slabs and lava, despite them being lower than full blocks at the same Y level as the lava, which they can pathfind onto without issue.

If you make a pen of bottom slabs around some lava sources and place a strider in it, it will be unable to leave on its own, though it can be pushed or ridden out.