I'm having this same problem in a couple of games now and I'm thinking it's this API Script. I noticed while playing last night that there were some spells (Chaos Bolt, Cure Wounds) that were not pulling up the Level Cast prompt. While poking around trying to figure it out I realized that Chaos Bolt wasn't even set to output the spell, it was supposed to be rolling a ranged spell attack and damage but it's putting out the spell text instead. I checked another game that I was using the same API for and when I cast Witch Bolt it didn't prompt me on what Level to cast it, and also didn't mark the automatic Level 1 spell slot as spent.