As this is a SYSTEMIC insecticide, the poison is taken up by the plant tissues and will therefore find its way into any embryo fruit. While the manufacturers will claim this is harmless, do you really want your home grown fruit contaminated in this way?
The leaf fall is probably a coincidence, as there is no obvious reason why the insecticide/acaricide should damage the plants. Possibly you sprayed in hot sunlight and the leaves were damaged when wet. Or if the trees were recently transplanted, it could be the shock of moving into permanent positions and drying out?

Are these trees in the ground or in pots, and how long have you had them?

I sprayed my damson with the same stuff this spring as a last resort to save the tree as it was looking very sad after a severe infestation last year and the same thing was happening again.(Some of you may remember). I was planning to use a garlic spray but left it too late. It worked and you can see the difference between the sprayed parts and the higher branches that I couldn't reach. The manufacturers have cleared its use for apples but not cherries. There was certainly no leaf drop so I don't think yours will be connected with use of the spray. (The damsons were just forming and I haven't decided whether to rislk using them!)