When I made a map, I decided to expand it after initializing it at my home base. When I did, it froze up the map display, including my character walking on it and the mapped area, and it didn't expand the map's visible area.
I made another map, and that one worked fine, so I figured I'd restart to see if that fixed it. Instead, it made certain blocks invisible, and some entire chunks, as well, though I could still interact with them. Playing with the video settings to attempt to fix this made the issue worse.

Steps to reproduce:
1. Make a map (eight paper surrounding a compass)
2. Activate the map by right-clicking
3. Attempt to expand the map (eight paper around the map)
4. Attempt to expand it again
5. Make a new map, and activate it in a chunk just outside the area of the first map
6.Save and quit
7.Reload the game from the start menu without closing it out entirely (for me, this caused the wood blocks in my chunk to become invisible, as well as stone and lava in nearby chunks)
8.Fiddle with Entity Shadows and Smooth Lighting in Video Options to make the issue worse (for me, this meant the entire chunk I was in becoming invisible, as well as not seeing any blocks not exposed, so I could see through the ground and find distant caves)