yep, tested in 8.4 2018-07-26 with no hals, single contract with 3 lines. The contract was never unOKed. Only the first line gets invoiced, all other lines are never invoiced. Will try to report a bug.
Hi, Paul.
Sounds like you're talking about REST API. And that your are overwriting data with older values if B managed to read record before A finished to update it. Classic conflict resolution ...