Polygon positions changed in Fusion when importing designs from Eagle

[huebnerX4YD3]

While moving projects from Eagle to Fusion Electronics is discovered that the positions of polygones change (there is a conversion from metric to imerial and then back to metric somewhere). In Eagle as well as in Fusion my Boards are set to MM.
Looking into the BRD file, the grid setting are also all set to mm:

<grid distance="0.25" unitdist="mm" unit="mm" style="lines" multiple="4" display="yes" altdistance="0.125" altunitdist="mm" altunit="mm"/>

While positions of Vias/Holes/PCB-Dimensions stay at the same, the location the positions of the polygone corners are different.
This is the case for projects (containing sch/brd) as well as simple brd only imports. For simplicity I used only a board her...

Example:
Eagle view of a square PCB with a Polygone and Dimensions:

 
Same board in Fusion after importing is as described here: https://www.autodesk.com/support/technical/article/caas/sfdcarticles/sfdcarticles/How-to-import-exis...

 
I know that my polygone width is 0mm in Eagle, but I build my boards like that in the past. Regardless I would expect that the polygone to be exact in the same location as in Eagle.

[huebnerX4YD3]

Update:
I guess, I will get a "don't do that" here...

When I change the polygone size to something != 0mm, like 0.2mm and then make all polygons 0.1mm smaller in all directions, the import is correct.

So at least I have a workaround now. Which requires to touch all Boards before importing them.
Or is there maybe something that I missed which whould not require editing all the old projects?