Hi Al..!
If you can find the casing that failed to extract, take a look at the rim. If it is pretty well "gouged", as the extractor rode back over it - then I would very slightly add a bit more tension. Or, your chamber is slightly rough - but if it were, I suspect you'd have more FTEs.?? Anyway - try adding a touch of tension - then shoot the 1911 till you have about 400 - 500 rounds through it. My guess is that the problem will go away as it's broken in.
On the release - be sure your right thumb isn't snicking it up on the recoil. It's been known to happen.
.. As well, strip the firearm, and insert a mag with a few rounds in it. Without the slide/bbl - insert the slide release, and check that there is clearence between the cone of the bullet and the inside tang of the release (if it contacts the cone - it will also engage the slide-stop). This can be adjusted via the mag lips holding the cartrige properly at the pick-up/release. If the shell is being held on center, it should not contact the release tang... You can try another mag, and see if there is a difference...
HTH!