Play a note with a long decay or release then select another patch and it only switches over to the new patch at the end of the decay/release a period and the new patch plays normally. If you select another patch during the decay/release then immediately press a key the patch switches over but you don’t get the full attack until you hit a second note.
This was happening to my changing from ‘Whistle Set’ to ‘Lead 6-VSet’
I guess this is to allow a note to finish rather than abruptly stop when you select a new patch…