Access and SharePoint Integration May Be Broken

I am neither MVP nor Microsoft employee, but there's one piece of advice which might be helpful to you. According to the build number, you currently use the Current Channel of Office. My recommendation is to try to reproduce the issue with the three Monthly Channel builds (here is a list of the build numbers, here is an instruction on how to change channels, and here is how to install a specific build).

This has the following advantages:

• If this is a blocking issue and it doesn't occur in one of the monthly builds, your users can continue working.
• If it fails even on old builds, you know that the issue is (probably) not Access-side but Sharepoint-side.
• When the bug report reaches Microsoft, knowing when the bug was introduced will help them fix it.