First I'd suggest you take a close look at what's going on during the failures. Supressors tend to over gas actions when installed on normally functioning rifles. Failure to eject, in my experience, is from under-gassing or other issues. I'm not saying it's impossible that over gassing is causing failure to eject, it just tends to be lower on the list.

How many rounds thru it supressed and un supressed? Any changes? New ammo? What ammo? What is the ejection pattern change when you add the can?