Flickering with Caseta 3-way switch setup

We have an LED light in our laundry that is controlled with a 3-way switch at each door. We replaced one of the switches with a Caseta in-wall switch (PD-5WS-DV). We jumpered the other switch, as instructed - at first, the light did not work at all, so we added the LUT-MLC, and now the results are inconsistent.

If the light is off, and the toggle switch is down, when the toggle is switched up to turn the light on, it flickers for a minute, goes out, and comes on solid, and works fine. It can then be turned off from either the toggle, or the Lutron. However, if turned off from the Lutron (leaving the toggle switch up), if we then try to turn it on with the toggle (setting it to down), the light just flickers forever - flipping the toggle has no effect (doesn't turn the light back off), the only way to correct it is to turn it off and on again at the Lutron.

Any clues where we might have gone wrong on the wiring? Apparently, the electrician who originally wired the house may have taken some code "shortcuts", and there are other fixtures on the same circuit.

We have some other of these Lutron switches installed, and they all work great.

It could be one of two things. Either the PD-5WS-DV and the mechanical 3-way switch aren't wired properly, or the LED isn't quite compatible with the PD-5WS-DV.

This would be something that we would need to talk to you over the phone. Can you call our 24-hour Technical support at 1-844-588-7661? It will be quicker this way.