I used to had issue with false alarm. Mine was not due to flying bugs. Mine is mostly due to cloud. I have so many issue during the day and summer season. Try to pay attention whether you are experiencing this the false alarm in the dark of night. If you do not have any issue at night, Look for the BOSCH that has tritech. It is not the one you mentioned in the link. I have good luck eliminating the false alarm with this sensor. Take a look at this thread.
I have no affiliation with bosh. I used a lot of their stuff. I feel your pain about the false alarm. I hope the bosch can help you.