I had that problem also. I was hoping the delays would trail off with the new delay patch overlapping on top. Here is what I wrote to them
(problem) I am referring to the spillover between presets and not the bypass spillover (which is great!). What I hear is that when I change patches, the spillover also changes to the new patch, which creates some unpleasant sounds when changing to certain patches (like your preset 4:1 with high feedback). If there is a way to do it like other processors where the old patch spillover remains the same and simply fades away, and any newly inputted notes come through the new patch. Such a design would increase its usefulness, as well as doing away with ackward changes in sound. Currently I cannot use this feature.
(related problem) I understand that with certain delay types that the tap tempo delay change will cause the unit to pitch shift (tape mode and vintage?), which to me is fine within the patch, but the problem I am having is when switching patches, it makes some really bad sounds depending on the settings (a long delay to a short delay patch and vice versa).