Unfortunately, it seems like CreateGPSDDraft function doesn't work with multiple results if results are taken from saved files.
The only workaround I was able to find it's run tools in Python script and get results 'on the fly'.
CreateGPSDDraft function works with multiple results I got in the script.
Hopefully this issue's going to be fixed because for some workflows it's necessary to run CreateGPSDDraft function with multiple saved results as parameter.