Hi Alex,
The Error and screenshot you sent are usually indicitive of a record being Archived. There are a few reasons this can happen (like syncing with separate QuickBooks files - typically accompanied by conflicts as you mentioned), but its probably best we investigate this one offline together.
Can you shoot me an email at Success@method.me with the Customer and RecordID(if you have it) and I can take a look.
Thanks Alex!
-Ben