I have a similar issue with the Doemenel line. I picked up the letter early on, then when I reached this quest I spoke to the Doemenels and didn't mention I was carrying the letter (asked about the trials), so got asked to retrieve it. I then stole the Jewel of White March and tried to hand in the letter and the jewel, but the conversation option wasn't available.
It wasn't a blocker for me because I could fall back on the Dozens, but I still have that quest line (A Two Story Job) in a stuck state.
