I discovered that importing an XML file containing a repeated measure drove me crazy until I deleted all the repeat signs and reconstituted them. The problems was that after repeating the vamp, the music unexpectedly skipped back to measure one. Apparently the XML file (from Finale) created overlapping repeats (particularly in grand-staff style instruments) with a combined repeat but also individual repeats on the separate staves. This seems similar to the extra time signatures added by XML imports on occasion.
I don’t know that this is something Dorico is responsible for handling, but certainly this is another thing worth knowing for those who import via XML.