Update configured Quote Line in BPM

When calling QuoteSvcContract.Update() in server-side code, I find the configuration data is being deleted for any lines that have configured parts. The QuoteDtl lines themselves remain intact, but ANY change to one of them results in the GroupSeq value being reset to zero when the dataset is returned, and the relevant PcValue records are gone.

As far as I can tell, I’ve been completely scrupulous in following what the trace log records when making the changes. The dataset passed from the client looks identical to the one that gets passed within the BPM. But the BPM wipes the configuration whereas the client call doesn’t.

Anyone any idea what’s going on here?