I have heard of this happening a couple of times. The whole program runs through as normal and then starts over and repeats itself on and on and on… not good.
Clearly the solenoid valves are opening and shutting and are not stuck on so the issue can really only lie with a fault in the control box.
On both occasions when this has happened I have replaced the control box and it has fixed the problem. So if this sounds like you then that’s most likely your solution!
For help or advice with these issues call Andrew on 0400044236 or email firstname.lastname@example.org