188.8.131.52, 184.108.40.206, 220.127.116.11
( This bug was marked as "fixed" in the current changelog, but is still in the current update.)
Windows 10: Yes
Xbox One: Yes
Mobs of all types are able to spawn on redstone components. Redstone being spawn proof was specifically added to java around 1.9, A lot of people use redstone dust to mob proof builds. it's a simple way of preventing accidents while not torch/slab spamming everything.
Please note that mobs will spawn on top of ALL redstone components.
And Pistons of both types.
Hopefully this can actually be fixed in the next update <3