I had that problem with enamels too. Here's what I did.
First, prime the tracks. It doesn't have to be the expensive Tamiya primer. I use the <$1 a can stuff from WallyWorld.
Next, switch to Tamiya acrylics. I've never had any issues with paint flaking off after making that switch.
Lastly, when the acrylics have dried, seal them with Future.
You may not necessarily have to go with Tamiya acrylics; but at the very least, prime the tracks. After that if you want to try the enamels again, go ahead.
HTH
Richard S.
On the bench: AFV Club M730A1 Chaparral
On deck: Tamiya Marder 1A2
In the hole: Who knows what's next!