Hi Vero,
the crashlogs have been sent to the info@ address.
In the meantime I tested the following:
Delete the Spotlight index and force it's rebuild (https://support.apple.com/en-us/HT201716)
Immediately after deleting the index alfred does not crash while entering the two SPACE characters
After a night of rebuilding the index Alfred crashes again
There seems to be some content in the index that does not match Alfred's requirements.