This looks like bug 51121, “Documents produced by LO 3.5.x and 3.4.x fail to open correctly when sent through Outlook Web Access”
It appears (based on the bug report) that the issue is in the compression of components of the file. I’d suggest you keep an eye on that report for the latest details.
Update: Fix has been pushed to master and to the LO 4.0 branch. Please bang on this and report any failures to the bug.