The extractor was replaced at one point in time, incorrectly. Remington extractors can be quite fussy and aftermarket versions may not have tensile requirements to function as new. I had to replace one on a standard LA and handed off to my smith since the tensile strength was giving me fits. He ended up heat treating and carefully resetting in bolt face. Works flawlessly now. My smith feels unless OE part from Rem, he had to heat treat to get aftermarket to work correctly.
700's do not have a Robust extraction system and if you hit too high of pressure and get web expansion on case, it may not extract the case. Pretty much well known deficiency in the 700 system.
Can't really see for certain, but looks like web ring may also be involved.
I wonder if Rem improved this on new 700's?