So, not sure how to describe this properly, but I definitely have video.

Messing with redstone, found a strange block update behavior that activates while setting a redstone in a Chess Knight's position away from water connected to an observer facing toward the Water or Lava.
Breaking just one piece doesn't disable it, but both will.
Adding just one back won't enable, both have to be present.

I am so confused.

Sorry for the lag on first video, encoding issues (fixed in the second, using lava for a slower pulse)

https://youtu.be/C664_cRT3Hg

https://youtu.be/4rMUV6nrQyo