Boot/trunk locks itself in cold weather when car is started

[yaris_driver]

I have a 2015 model Toyota Yaris XP130. No smart key, but remote key with two buttons (lock, unlock). Trunk does not have a keyhole, only one button that must be pressed while opening.

Sometimes in cold weather, after I have started the car and driven around, when I go open the trunk I notice that trunk does not open from the button on the trunk. When I use the remote key or button on driver's door to unlock the whole car, then I can open the trunk using the button on the trunk.

I noticed this issue already during last winter, but during summer time there was no problem.

So buttons and lock mechanism seem to work to some extent and nothing is permanently stuck, but for some reason in cold weather, the trunk just decides to lock itself after starting motor. All other doors stay unlocked and with no problems. Any idea what could be the problem?