QueryFeaturesAsync returns empty polyline

[ERDMANN-Softwaregesellschaft]

Hello,

i have a problem when i call QueryFeaturesAsync. I expect a polyline with two points. But i get an empty polyline. If i make the request over the website i get the expected result:

Polyline:
[96447.22159999982, 432016.3209999986, -0.46730000000388827] , [96447.2210999988, 432016.32189999893, -0.46730000000388827]

Now i make a query with the ArcGISRuntime .Net (Version 100.15). The FeatureQueryResult contains a polyline with no points:

But when i look with fiddler the response of the webservice request contains the correct points:

Could it be a problem that the line is to short? I hope anybody can help me to find out what the problem is.