I made a lava pool for striders with fences keeping them in, and eventually the striders decided to jump up on the blocks housing the fences. After this, they would remain stuck there and never return back into the lava. I later went on to push them back in, but they would eventually once again climb up on the blocks and remain there forever. Keep in mind that it takes some time before they start doing this, but if you have multiple striders it should be noticeable fairly quickly.