Fence gate despawns when a sign is place on a connecting block

When placing a sign either on the block below a fence gate or any surrounding block of which would impede the block in which the fence gate is located the fence will simply despawn without any item being dropped and would be replaced with the sign. I have not tested this on any other versions except 1.16.100 and additionally I tried this with trapdoors and scaffolding but in those cases nothing happens which leads me to suggest this is a bug.