This website, which is concerned with the 414th BS, mentions that the 414th bombed Feldkirch on 1 October 1943, rather than the primary target of "Rusburg" corrected to "Ausburg", i.e. "Augsburg"):
Scroll to 2nd page of the missions list and note the "clickable" comment in the box on left side of the 2nd page:
http://www.reddog1944.com/Missions_T...bat_Action.htm
It appears some of the information there was provided by an Austrian researcher, Gehard Winkler (who gives a perhaps no-longer valid email address) :
http://www.reddog1944.com/97th_BG_Co...orrections.htm
As to what happened at Feldkirch there are a couple of Austrian websites that give some details (Google translate gives a rough English translation):
https://www.vol.at/feldkirch-bombena...jahren/3720822
https://regiowiki.at/wiki/Luftangrif...._Oktober_1943