These symptoms are consistent with Brown Rot, and the infection period likely took place a couple weeks ago or so. Depending on the fungicide(s) you've been using, perhaps some of the ingredients happen to be less effective against this pathogen compared to others. Orchard growers also rotate fungicides in their spray program, in order to switch out periodically what chemical they are using so it acts differently on the disease spores in question so they can't become resistant to a single treatment type. This might be harder to do at a home scale given the expense of having additional fungicides to use, but is one option to try in another year if your current method of preventative spraying is not effective enough.

The link in the pest management section of our Growing Stone Fruits page that directs you to the Virginia Tech pest management guide publication is a thorough resource for determining which pesticides to consider using, when, and at what dosage rate to combat the typical ailments of cherry trees. (It's a long document, but you can search it for "cherry" or "brown rot" to jump to relevant sections.)

Miri

Yes, Brown Rot is unfortunately one of the most damaging and commonly-encountered diseases among the stone fruits grown in our region. Weather can interfere with spray schedules and sometimes conditions are just right to promote infection regardless of treatments applied. You seem to be using a good diversity of fungicides, so hopefully next year's disease cycle can be successfully interrupted with your spray regimen.

Miri