Games resetting to title screen on an Intellivison III??...

So, I LOVE the Intellivision! And last month, I purchased an AV modded Intellivision from a top-rated seller on Ebay. I hooked it up and played Astrosmash, however, the game would reset to the title screen after a few minutes. The same thing happened with Atlantis.
I cleaned both carts very well, and the same thing kept happening.
I'd love to know what's causing this issue, because right now, this system is not hooked up, and is just collecting dust.

How long ago did you get it? You may need to contact the seller as the issue may have to do with the mod.