Multiple catalytic converter failures in multiple vehicles

[Donmatteo]

If your using an oil that lighter ends are vaporing off, then you could be burning them in the converter. A new and a used oil analysis should pick that up. It could be ppm of an additive that does not play well. What are you using? I am in the gasoline camp tho. You don’t happen to have a very short daily drive do you?

Not my thread. I'm not the OP

 

[smurfslayer]

I hope you find answer & thanks for the update.