This is  a mod-related bug named the MISSING UIMAPPER bug.  It happens whether you change your mod loadout mid-session. To avoid it, open up the game, select all mods you want, choose apply, play. If you go back to the mod screen and apply another mod loadout (either by adding or removing mods), the game UI will break, and you'll be able to end your turn without selecting research, moving your units, choosing production for your cities, and other weird effects. If you want to play with different mods, close the game, reopen it, then select your mods.

 This works to avoid the MISSING UIMAPPER bug on any and all mods you choose. MISSING UIMAPPER can ALSO show if you open the game, try to load your last modded game by clicking "continue", fail, go to the mod screen and apply the correct mods, then load the game. Always always always make sure you open the game and select the mods as the first thing you do. If you're in doubt, RESTART THE GAME. This helps avoiding the bug every time.