Where Prompto is in a relationship with Ignis that begins before the roadtrip but all his canon interactions with/about Cindy are the intact.

Why Prompto acts that way is up to the writer/their interpretation. A crush, platonic idol worship, etc. Similarly how Ignis responds is up to the writer but I'd like some angst and ruffled feathers.

DNW: permanent break-up, cheating (accidental emotional cheating on Prompto's part is fine)