Alfresco+DotCMIS: Folder.GetChildren returns some duplicate items

When I run DotCMIS' Folder.GetChildren on an Alfresco server, I sometimes receive a few duplicate items, for instance:

dir1 dir2 dir3 file1 dir4 dir5 file1 dir4 dir5

You can see that the last 3 items should not be present.

Here is my code, and debug showing one of the duplicated items:

Here is the detail of the lower part of the screenshot, showing two items that represent the same folder. You can see that both items have the same name ("cmissync") and same id ("workspace://SpacesStore/385da00c-8b3a-4736-b3e5-1ca1c2ff1cac").

Is it a problem with my code? (line shown in screenshot above, full method here)
Or is it a known problem with either DotCMIS or Alfresco?

I have tried to analyze the CMIS network traffic, but unfortunately the packets content is not readable, and I could not reproduce the problem when I tried on a freshly installed non-HTTPS Alfresco.

Upgrading to DotCMIS from 0.4 to 0.5 fixed the problem.