Yes, the old fashioned button can get stuck in the inside position, especially after rain or cold weather. Then the closing mechanism does not latch in. Happens to me almost every day. Normally, there should be a warning light that the dooor is not fully closed, but with the stupid Grenadier electronics, this light sometimes may not come up.
Reason is a lack of lubrication, so the button stays inside. I sprayed a bit of WD-40, which helped for a few days. But the best is a visual quick check to see if the button is out. Since the Grenadier is anyway a bit like an airplane, such a pre-flicght check is ok.