>>73043704It's probably mostly this (
>>73043805) but the fact that Matara is close to Kyo, who may have had a hand in Sayu's torment, and is close friends with 39Daph, who definitely had a hand in Selen's torment, post termination, puts a huge elephant in the room with Mint that will haunt her every performance until she tries to collab with Doki or at least mentions her name to clear the air - something neither performer has done thus far.
Despite all their heartwarming collabs together, in which Selen and Pomu appeaer to be having an absolute blast together and act as the closest of friends, it seems no one associated with Nijisanji is above suspicion of being part of the clique that helped drive Selen to suicide anymore, and that fact inevitably taints the air in which Mint performs.
Personally, I find it hard to believe, given all the moments they shared that were along these lines:
https://youtu.be/BpAIgtdOBxkBut my belief doesn't remove the purple miasma suffocating the green ghost, that could be so easily blown away with one simple nod toward the other by either performer.