Minecraft 18w10d, Minecraft 18w16a, Minecraft 18w20b, Minecraft 18w20c, Minecraft 18w21a, Minecraft 18w21b, Minecraft 18w22a, Minecraft 18w22c, Minecraft 1.13-pre1, Minecraft 1.13-pre2, Minecraft 1.13-pre3, Minecraft 1.13-pre4, Minecraft 1.13-pre5, Minecraft 1.13-pre6
Default bundled Java runtime, Windows 10.
Any variant of non-full block with the property waterlogged=true will trigger auto-jump when being walked into from air, whether auto-jump is enabled or not. This is true for chests, fences, walls, glass panes, iron bars, slabs/stairs with walls next to them, etc.
In the case of fences, the player will continuously jump, since it is not possible to jump over a fence.
This only occurs when the block is being approached from a side out of which water is not flowing. (In the case of it going towards a cliff, etc.)
attached linked (the attach kept giving me an error) a screenshot that demonstrates paths (with arrows) which should recreate this bug.