Regardless of the position of the clutch lever, my '08 will not crank if it is in gear and the side stand is deployed. Maybe those times when you tried to start it with the clutch pulled in was because it was in gear, but the side stand was deployed.
Maybe that's because you are talking about an '08 C14..... and he's asking about his C10... which is totally different.... doh......as for the o/p's question....
unplug and replug in the harness connections for both the side stand switch, and the clutch interlock switches a couple times each, after spraying them wit some WD40... they may have a compromised, or slightly corroded/resistive layer on the pins.
Also, either switch is prone to sticking after many years of use.. so getting to both switches, and spraying them to flush them, using WD40, cures 90+% of these intermitant failures (use the red snooter tube on the can, and shove it under the rubber boot of the sidestand switch, and spritz it good, making sure the rod on the switch moves fully both directions without any gritty feeling...).