I am trying to reproduce but it all works here, just remember this:
for autoexp, a value of 0 means auto and 1 means manual (it is a menu with 2 entries, not a boolean -- not our choice, this is how it is defined in video4linux, the full parameter actually has 4 entries but we only support 2).
also, because the USB specs do not provide an auto gain parameter for webcams, our auto gain parameter is slave to autoexposure. So you should first choose your autoexp setting and then autogain.
when I change autoexp to 1 in script.cfg of FirstPython and then save to JeVois with CTRL-S, the video turns darker, and, looking at the Camera tab in the inventor, the autoexp parameter is indeed in manual. Setting it back to 0 has the reverse effect.