(gtkam-0.1.4-6) When started and asked to detect the camera, it's successfull. It's also able to load the proper protocol module, but fails when trying to access the device. "--debug" output attached.
Created attachment 76504 [details] --debug output
(gphoto2-2.1.0-4)
Created attachment 76524 [details] output of lsmod
gphoto2 --auto-detect --summary is an easier way to reproduce this
Created attachment 76525 [details] strace of the gphoto2 command
Since it's now working for you, I guess just keep an eye on it and re-open if it recurs.