I can continue working after the error.  no need to restart.  but there's actually no way to load that preset successfully, after the error the box is still on the previous preset.

Do you mean it's a problem with one particular preset?  And this one preset never loads successfully?  If so, it would be helpful if you could export this preset and send it to us so that we can take a look at it.  With the preset selected, if you press on the More button in H9 Control, there's an option to export a preset.  You could email it to my user name plus @eventide.com.