Alko ATC brake problem

Not so much an ask for help as a question to see if anybody has had this problem. Caravan back form service, a 3 mile tow, and started to manoevre on site to park it. Mover struggled to move van forward and with mover disconnected could not push it by hand. Brakes making a creaking sound. Service outfit came to house and diagnosed problem (correctly) as a partly on ATC braking system.

It apears that in removing the 13 pin socket I must have unmade the contact and in struggling to get the plug out remade the ATC contact again briefly. The ATC system then got part way thro its self checking system (the whirring noise at normal reconnection)  leaving brakes slightly on. A reconnection cured the problem but it was initially concerning that the brakes were stuck on particulalrly just after a service.