I have the following setup all on a powered USB hub attached to a RPi3mb+ running the latest updates (just did an apt-get update and running the 1.7.6:
heq5 Serial to USB
canon 6dmII
logitech 905 webcam attached to the 9x50 finderscope.

RPi3 is attached to my local wifi network and i control it using VNC.

I consistently have issues with webcam. it either stops responding, cannot reconnect after i try to disconnect from the indi server dialog.
(I even tried to run KStars remotely and indi only on the RPi but even on my Wintel kstars is crashing after some seconds of looping in guide.)

At first boot i get the internal guider to loop for a while but then after few sec up to few minutes i have errors on the V4l2 input (stream or capture). it often ends up with Kstars crashing completely. I then need to restart ilocal indi server is still running.

i am attaching latest log file

PLease I need help!.

I see your indi_v4l2_ccd driver throws a lot of input/output errors e.g.
Finally it crashes after:
This issue must be looked into by the maintainer - Jasem aka @knro. I will not be able to help much.

I encountered before some memory issues in the driver, but they were difficult to pin down. I will try later today to see if I can reproduce this issue and then valgrind it.

after some thinkering i have a more stable situation:
- I guide with PHD2
-i changed added to the /usr/boot/conf.txt
dwc_otg.fiq_enable=1 dwc_otg.fiq_fsm_enable=1 dwc_otg.fiq_fsm_mask=0x3

Any idea why these settings would help?

Honestly i did not look into it much but found a post that mentioned it solved issues of connectivity with USB/Webcams.
which seems to match my own behaviour where it works fine to start with and then cannot find the device on the port.
www.raspberrypi.org/forums/viewtopic.php?t=197089