can you please try to reinstall the client from MyStandard or www.standardinstall.com? As you mentioned maybe it's related to MacOS client issue: https://partners.hansaworld.com/forum/viewmessage/13/3376
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 ...