Unable to continue the game. Unable to continue the dialogue with Shyka in the 'Complete Shyka's task' quest

Platform: Steam, Windows 10 (64).

Do you have any mods? BagOfTricks & CheatMenu, but both mods are disabled (In the mod manager).

Please explain the issue is in as much detail as possible:
When I do the “So Shall You Reap” quest, I first do the “Talk to the Lost Prince” and “Complete Magdh’s task” quests.
Then I start the dialogue with Shyka. After 2 phrases, the screen loses any interface, the dialogue disappears too. Buttons 0-1 (which are for selecting phrases in the dialogue) and the spacebar (to confirm the selected cue) don’t work. The mouse clicks don’t work either. When I press Escape, the main menu appears, and at the bottom I can see the dialogue - but I can’t continue when i press esc!

The game at this point is completely broken - I can not do anything but load save again and again (I can not even make a save in the dialogue). Dialogue can not continue - and the game can not be completed!
Attached save and video.