2011 CVP- Noticed today when I pressed my trunk release it made a rattle sound and I had to press the button several times once it released the trunk so I could close. Feeling that maybe this was a lubrication issue, I proceeded with some silicon spray. Still happening - your thoughts? Thanks!

Latch is failing, you may need to replace it.

It might simply require an adjustment of the striker at the base of the trunk, or the latch itself.

Have you tried "closing the trunk latch" on a screwdriver shaft, then seeing if the trunk release will operate properly?

The rattle sound is unusual. HOw does it work with the key?

So when I attempted to use the key, none of the keys I have will turn the lock. This has worked in the past though the majority of my access was with the button release. I have sprayed the cylinder - still n/g. If the trunk cylinder needs to be replaced, what have you found to be the best replacement? Thanks

The key cylinders corrode in these things pretty bad if you don't use them regularily. Mine is a crusty mess and if my remote release ever fails it'll be a case of fishing for the release handle from the back seat.

Does it behave any different if you hold the button in for an extra second?
Have somebody push down on the trunk while you hold the button and then pull up (keep holding the button). Might give you that one time access if things are kind of working. Just don't close it again until you get an alternate release "string" strung. =-)

So i used some PB Blaster on the lock cylinder and the trunk lock/key now works. So the original problem remains, when the trunk button is pressed the release opens the trunk but the latch is making an electronic rattling sound

Be warned that lock cylinders should be lubricates with dry graphite lubricant.
Using an oil/grease (your PB Plaster) can gum them up over time.

Still sounds to me like you need a new latch mechanism (solenoid)