polygons have wrong coordinates when source CRS != config CRS

Hey people, there seems to be a bug when the config CRS and the source CRS (from the tif files) do not match.

The use case: source CRS != config CRS

behavior: The saved polygons have the desired config CRS, but the coordinates of the polygons are in the source CRS. When loading the polygons into QGIS they are in the wrong place. Manually setting the polygon CRS to the source CRS gives the correct polygon positions.

Tested with source CRS = EPSG:25833, config CRS = EPSG:25832

Suggestion:

1. Polygons should be transformed into config CRS before saving them
2. no config CRS should save the polygons with the source CRS, instead of giving an error.