When going from Spectator to Survival mode (gamemode 3 to gamemode 2) player can't place blocks, mine or destroy blocks, or place items from inventory. Highlight block appears to be turned off.
Switching back to Spectator and then Survival again doesn't fix. Survival mode is hosed after being in Spectator mode.
Creative mode appears to be fine after Spectator mode.
Gamemode 2 is adventure mode. Gamemode 0 is survival mode.