Cloned Objects on TP Groups

I was working earlier today with a couple of cloners each cloning onto separate TP groups and everything was working wonderfully.

Suddenly something has gone terribly wrong and I can't find the fix for the life of me.

The particles are still behaving properly but the cloned objects are effectively disappearing the frame after they're born. The clones are primitive sphere objects. After the first frame there's a single edge that travels with each particle where the sphere should be.

I've removed all effectors from the cloners and tried playing with the particle size to no avail. Any other suggestions of things to check?

Darby Edelen