Endgame towers unable to influence

After completing most endgame towers I am unable to influence their area with tablets. Last i've done was a sinking spire. Map was completed. Clicking on the tower does nothing (the dialog with the 3 tablet spots doesn't appear).

Also, some of the towers finished a long time ago (before the endgame/tower patch) have their tablet spots open when clicking them. But when pressing the "influence" button, i get "Tower already used". If it was already used, why did i see empty tablet spots?!

PS: Hopefully these 2 issues are not linked somehow (i.e. the unclickable tower "migrating" its tablet spots to a tower finished some time before).

Please fix these towers, it makes the endgame really unwelcoming.