Stairs are weird. 

There are many stair bugs. 

Visual Stair Issues:

• Backs of corner stairs have texture overlapping
• Waterlogging looks wierd, and doesn't work properly
• Special blocks don't connect to corner stair backs
• Can cause lighting issues, especially with night vision

Non-Visual Stair issues:

• Not becoming waterlogged when stairs that have to become corner-varients are placed in water sources (sometimes) 
• Refusing to become waterlogged, then you reload the world and your room is now flooded because you tried to waterlog it 100 times (only ever happened to me with stairs) 
• Waterlogged stairs underwater become black voids sometimes with night vision. 
• Special blocks don't connect (this time the blocks in question behave differently. ) 

Some of these are directional, meaning it's tedious to reproduce them. 

These can happen more frequently with lag: my phone experiences these all the time; however my xbox or on a (relatively fast) Windows device, rarely.