I've hade this Bally Vector game for a few years and it has been working flawlessly.

When I started the machine today, started playing a few games and wasn't able to lock the balls after shooting down the upper drop targets.

If you are familiar with this game, you know that in order to get into the lock area (the ramp on the left) you need to shoot down the three drop targets in sequence.
Like 1-2-3, not 2-3-1 or 3-1-2 etc.

I noticed that if I shoot down the right most DT (3) and then 2 and 1 in order, then everything is OK.
But if I shoot at 1 first and then 2 and 3, then the light in front of the 3 DT is lit solid, like it's waiting for it to be shot down, but it already is?

In testmode all DT switches registers accordingly, everything seems to be working fine.

Any ideas?