Hi @Regina Henschel ,
Thanks for finding this, I filed a bug with the team in that covers Oart integration in Word. I do not currently have an ETA for when the fix will be deployed, if I receive one, I will let you know.
The OOXML standard specifies type ST_Coordinates as type of the attributes of the effectExtent element (§18.104.22.168). The type ST_Coordinates can have negative values, see §22.214.171.124, then ST_CoordinateUnqualified simple type (§126.96.36.199) or ST_UniversalMeasure simple type (§188.8.131.52).
But when I use a negative value, Word does not interpret it correctly. Instead all DrawingML objects are removed from the document when loading it.
It seems, that Word does not support negative values. In that case, it should
a) replace the negative value by zero.
b) only change the affected DrawingML object instead of deleting all of them
c) document the behaviour in [MS-OI29500].