The failure to feed (FTF) and failure to eject (FTE) are most likely caused by the ammunition. Its my guess you are using a cheap brand 115 gr load? You can prove this by removing the comp and shooting the gun. If it runs... GREAT! If not, it’s the ammo for sure. Now add the comp and run the same ammo. You already did this so we both know it is prone to failure but I want you to try it again anyway, but this time make sure you have a firm grip on the handle and lock your elbows. Make sure this is not a limp wristing issue. If you still get the FTF/FTE try another load in the 124 or 145 range. It should run excellent with these!
The LWD comp is very efficient. It requires a certain volume of gas to run correctly. The problem with some 115 gr loads is that they do not generate enough gas to run reliably (with or without a comp). Its like trying to run a dragster on pump gas. You need the correct fuel to run at speed and unfortunately, not all 115 gr loads will do it.
Lack of a channel liner will not cause a FTF/FTE. Don’t let that fool you into thinking its ok. You need to get a FP channel liner in your gun for sure. (Your trigger must feel really gritty?)