it may be the wires in the door for the central locking, getting the plugs apart is really a right pain in the arse of a job to do

if the locks are opening again it would point to something sticking

do they lock internally or not?

when i had problems with my central locking it was the module that was at fault, but i also broke one of the locking cables while i was doing the swap and then i managed to lock myself int the car and it wouldn't open

go to the door that has the issue and remove all the mechanism that does the central locking and see if it works when it's free, at least you can eliminate the motor and do a bit of guess work as to where the porblem may lie if it's mechanical rather than electrical

the boot popped nearly always tends to be the actual microswitch in the tailgate being dry, open it up and grease it and 9 time out of 10 this solves the problem

be careful though, it's a bit delicate