unix-guy
Master of RTFM
When you select multiple presets, the target slot is where the first preset goes and the others follow sequentially.Just thinking if this might be the cause...could it be that copying/pasting more than one preset at a time doesn't target more than one user slot? That the firmware "thinks" you mean one slot, instead of separate slots?
For example, select presets 1-5. Drag to slot 21. The presets will go to 21-25.
Also, there are no "user slots" for presets - or rather, they are all user slots (depends on how you look at it, I guess). The units come with factory presets installed, but any preset can be changed, moved/copied to any other slot or deleted.
Now, IRs are a different story.