Same is happening to me, but I don´t have any ships so maybe one of the AI ships is stuck. Its happening right after I hit the turn button and the AI takes their moves... then the turn button disappears. The game itself isn´t stuck, I can enter menus, planets etc.
This is with Twilight of the Arnor, 2.03 (latest patch) during the campaign mission "Apocalypse".
I loaded a previous save game from 3 turns earlier, but it gets stuck at the same time 3 turns later.