We have also noticed a decrease in range with the update to 6.05.xxxx firmware.
Pretty easy to document with the Flarm Range checker using last years files for comparison.

Yesterday I updated to 6.06 and upgraded my Flarmnet file and lost the Flarmnet feature at least with the other glider I was testing with.
The Flarmnet feature might be the result of updating some for the Flarm information on the other glider. (Mode S ID, did not change)
Going to test today with a glider that their flarm setting has not been changed to see if it is my Flarm or the other Flarm causing the competition # not to show on my butterfly display.

Brian