I also came across this issue today during a cube draft match. I've attached a screenshot of the issue. See I have three untapped swamps but the game would not let me cast the Liliana of the Veil that I had in hand. The screenshot was taken during my end step, but I tried to cast the card in main phase. Both by dragging it onto the battlefield and by manually clicking my swamps to tap. The game would not let me manually tap the rightmost swamp, it was like it was not there.
I also came across this issue today during a cube draft match. I've attached a screenshot of the issue. See I have three untapped swamps but the game would not let me cast the Liliana of the Veil that I had in hand. The screenshot was taken during my end step, but I tried to cast the card in main phase. Both by dragging it onto the battlefield and by manually clicking my swamps to tap. The game would not let me manually tap the rightmost swamp, it was like it was not there.