Car intermittently will not go forward after switching from reverse

[acollard]

Hello,

We have a 2006 Carryall 6 Utility cart that occasionally fails to go forward after going in reverse. It used to only happen about once a week but now this happens almost daily.
Note: the Cart always is able to go in reverse.
All 8 batteries in the 48v Array are fully charged, good connections, etc.

The Clubcar dealer replaced the switch; didn't resolve it.
I replaced the solenoid thinking it might be starting to fail since it always able go in reverse, but the issue still persists.

I was able to find a way to get it to fail going forward everytime by putting it in forward and reverse several times.
To get the cart to go forward again:
-I would would do the OBC reset procedure (always works)
-or travel in reverse for 10 or more seconds then go forward(doesn't always work and need to have )
-or wait 10 to 15 minutes in neutral then try again(mostly works).

So, now I suspect it may be the OBC, but earlier I thought it was the solenoid. Can anyone give me some hints or tell me that I'm on the right track troubleshooting this problem? Appreciate any thoughts.

At least, I could take it back to dealer since I can replicate the problem for them now.

Thank you,
Arthur