I'd give RA a call, but first try to recheck that trigger from the inside and out. It sounds as if something got moved out of place instead of broke. The normal culprit in AR's and AK is the trigger axis pin (the pin the trigger pivots on) which would be the pin directly above the trigger as seen fron the side of the lower receiver. You should notice right off the bat if that was out of place seeing one end stick out of the lower and the other side sunk in. The hammer spring is what holds it in place and you'll notice that as you look straight down into the lower and they'll be the two long spring ends along the inside lower wall pointing to the stock. Might as well check that both are that way. That click you hear/feel when you push the trigger foward is normal and it's the hammer being sprung back and engaged by the sear.
The second suspect would be the trigger spring. The XCR's t springs look wound up pretty tight. Nothing should be loose in there. If you see a spring flopping around most likely it would be that one. I rarely ever see springs just fail, or pins break or bend, but they do happen. I usually see that something wasn't put in right, typically with these pins being retained by another spring and not getting right onto the groove and then pins get worked out when they get fired or being carried on duty, usually in a vehicle that makes alot of vibrations (tracked vehicles like a Bradley or M113, USBP vehicles bouncing off-road all day, etc.).
Maybe someone else who is less lazy than me will post a high quality pic of the inside and outside of a lower receiver and compare it to yours. Or do the same to yours and someone should notice it. Hopefully it is a simple fix (9 out of 10 times they are) and you can avoid having the hassle to send it back. And let this not reflect on RA, or any other company, if something wasn't put in 100%. I can only imagine some poor shmuck (not confuse w/chuck-lol) at RA putting lowers together all day long and ONE f-ing pin that the sring didn't quite get into the groove out of 100 or so lowers a day. All guns, specifically semi and full autos, have all had issues like these.
Edited to add:
Seperate you lower from your upper. Hold the hammer w/your thumb and pull the trigger and gently let the hammer spring up w/o slamming into the receiver. At this point pull the trigger and the trigger should go back and spring foward w/o assistance. If it just flopping around loose, something is up w/the trigger spring (broke or not engage right). If it isn't loose but requires you to push it foward and feels like it's binding that's probably b/c it is. Check the trigger axis pin to be sure it looks the same on both sides and check to see it something is lodged in between the trigger and trigger hole, such as a primer, a piece of brass, or other debris. Look at it from under the receiver and use a flash light. If the trigger checks out, look at the hammer and make sure it is not canted and the pin looks to be in place. Doubtful that will affect the trigger as such. trigger parts require very litle lube and I recommend next to nothing b/c dust and dirt will collect on oil and grease right where you don't need it and can't get to it w/o a complete dissasembly of the trigger.