Can you confirm that you were playing on 1.23a? I have definitely completed the battle with both artillery captured on that version. Assuming you are on 1.23a do you recall if you captured brigade 1 or brigade 2 of the split? I never got a spit on my tests so that could be the root cause.
I have experienced this also, playing with the 1.23a version of the mod.
Also a different playthrough using the 1.23a mod i had captured one of the batteries and the enemy recaptured it, so i destroyed that one and the other and the same thing happened. I got the defeat screen and it had showed i never took care of the battery me and union captured.
But, this is still a great mod and very fun to play, so thanks to you guys for developing it. It has taught me to do a lot of saving during battles so I don't have to replay the entire battle. lol
(ex). Like when i played Shiloh, i had Pitts Landing taken and the victory conditions showed i had completed them all, but the game sent me to day 2 instead of giving me Victory. Luckily I had saved the game with a hour left on the timer so I reloaded the save and all I did differently was placed one of the Commanding generals right onto the flag and it gave me the Victory that time. I have had to do that in a few battles so far and I just finished Chicamauga.