Usually this means something in between steps inside a single piece of software. As in “interstitial ads”, which play, e.g., between levels of a game. In contex

Usually this means something in between steps inside a single piece of software. As in “interstitial ads”, which play, e.g., between levels of a game. In context, I think this means that GP doesn’t want to see something pop up and celebrate in between the steps of requesting a new OTP and actually being able to use it (such as copying it). (Also, for the record, since I’ve had people argue with or downvote me just for expounding on someone else’s point: this is not an endorsement of GP’s opinion, only an explanation.)