Could be that last round that fired was a little under charged..ie. not enough umph to fully cycle the slide which would account for the failure to feed. The 2nd cause that comes to mind, is that it may just have had a dirty chamber causing the spent case from the last round fired to stick a bit.
With my .22 lr conversion units for several 1911's, I've got to clean them each 50 rounds or so to prevent FTF problems.
Our Flag does not fly because the wind blows against it,
It proudly waves because a soldier's dying breath blows upon it.
USAF Forward Air Controller, 5th Spl Forces,
An Loc, lll Corps, RVN, 69-70, Vietnam Vet '69-'73