Hi, I work as a designer in a french company specialised in feedback taking and want to share some of my experience :)
A lot of our UIs rely on that kind of 5-star rating components, and just as you, we did the choice not to ask the user for a second tap to submit their rating.
However, some of our users complained about the rating control “disappearing too fast”… we quickly realized they had an interesting approach on how to give the rating
Let’s say that kind of user wants to rate 4 : they would tap the first star, then the second, … until the fourth one, in order to “fill” the rating control.
I did some research on how the “big ones” (Uber, Yelp, Messenger…) uses those 5-star controls and realized most of them ask for validation. I guess maybe that’s the reason ?
I only have guesses so far, no metrics unfortunately, so I don’t know how big is this phenomenon. Would be interesting to do some user testing about this.