Ok - got you this time.
I might have a HH schematic here in the pile.. as usual though, they are in the shed with no power and I don't get home till dark.
What should be happening is that the zero position on each reel is engaged.. the 100's reel is engaged to reset by the 9 position on the 10's reel and so on.. that tells the machine that the game is reset. What I think is happening here is that the relay that pulses the score reels ( should be in the backbox) is not engaging properly.. I THINK its labelled DB... it needs to be open when all reels are at zero... if it stays open then the game assumes the score reels are reset ( am I making sense?).
This relay talks to a switch on the score motor telling it to stop because all reels are at zero.
It the problem comes and goes like you say then im afraid its a very fine adjustment that required.. could be a dirty contact or misaligned switch that is slightly out.. check with your DMM

Hi, yes what you said makes perfect sense and thanks for going into detail for me.
In the backbox, there's the N,M,L,K for 10's,100's,1000's,10,000 & F relay which is the different style relay that switches the lit lanes when the ball hits the bumper...they all look good and I adjusted, tightened and cleaned contacts but I'm still having the problem...I'll keep tinkering. Maybe the relay that pulses all the score reels is in the cabinet so I might have to go through and  check them too.