diff --git a/src/p_mobj.c b/src/p_mobj.c
index 48fb94b92..7ce5267e5 100644
--- a/src/p_mobj.c
+++ b/src/p_mobj.c
@@ -2288,6 +2288,9 @@ boolean P_ZMovement(mobj_t *mo)
 		}
 
 		P_CheckPosition(mo, mo->x, mo->y); // Sets mo->standingslope correctly
+		if (P_MobjWasRemoved(mo)) // mobjs can be removed by P_CheckPosition -- Monster Iestyn 31/07/21
+			return false;
+
 		K_UpdateMobjTerrain(mo, ((mo->eflags & MFE_VERTICALFLIP) ? tmceilingpic : tmfloorpic));
 
 		if (((mo->eflags & MFE_VERTICALFLIP) ? tmceilingslope : tmfloorslope) && (mo->type != MT_STEAM))