Just wanted to chime in and say: I had that issue too, and I solved it by clicking on a bet type again and just placing an additional bet. Not sure if that helps solve the issue, but thought I would point it out! Only happened on the second race, and not on the third.
Thank you, Olivia. That suggests it is some sort of logic error in my code, rather than something funky about the web build itself. Probably just some way of using the app different from how I always do it! I'll get to the bottom of it.