Honour Mode, so I can't reload.
I went to the Captain's Quarters, had Astarion steal the shard off her. I think my DUrge was accused of stealing it first but as she wasn't the one who stole it, nothing happened. So I thought I'd be clever and quickly put the shard into the slot before the real thief got caught. Astarion got confronted next and a fight broke out, but the barrier didn't drop and the shard is nowhere to be seen. So I can't proceed with the quest or get the Blood of Lathander. There doesn't seem to be anything I can do to get past the barrier. I will just have to suck it up it seems. I was really ready for the inquisitor fight too. I was thinking about how I was going to approach him all night too. How anti-climatic and frustrating. If it wasn't on Honour Mode I would just reload but that's not an option.