I had this same issue, I'm sure it's something else, but I'll toss this out anyway.
Mine came to a head when I hopped out of the truck and it locked the doors behind me, and cost me $150 for a lock smith since LUCKILY, I had my phone in my pocket, rather than in the truck....
Got an electrical aftermarket accessories?
I had an alarm system that also had a kill switch so the truck won't respond if someone broke in and hotwired it.
Removed that, after noting the problem went away after I disconnected it's power supply. 6 or 7 years gone now? No problems.
A short somewhere would be my guess, but I'm not smart, and I'm lazy, so ripping it out was faster and easier once it seemed to help with the problem.