I dried all of the components and re-assembled everything and lubed all of the moving parts.
FWIW, armorers are taught to leave the internal parts of the frame dry, without lubrication. The exception is the hammer, which can receive a
small drop of oil on each side where it rubs within the frame. Not enough for it to run off and migrate to places other than the flats of the hammer inside the frame. Excessive lubrication can attract fouling & debris and sometimes accumulate into a sludge. This sludge can interfere with the intended movement of the parts (like the sear, drawbar, disconnector, etc). I had to de-gunk (technical term

) a 4566TSW because of an excessive amount of solvent/lube which had accumulated around the sear, hardening into a nasty mixture which prevented the sear from freely moving. It ended up being brought to my attention because the hammer started following the slide (sear couldn't snap back quickly enough to catch the single action notches on the hammer and hold it cocked during live fire). Once I cleaned the gun the "problem" disappeared and the gun worked just fine. The sear spring, sear & hammer all appeared in good condition. Just too dirty and fouled with a nasty sludge that gummed things up.
I will suggest the Hogue grips to her, but she may resist. She has small hands and part of the reason that she likes the 3913/14 is that it fits her hands perfectly.
Understandable. The Hogue grips will add just a bit of extra thickness and "meat" to the backstrap area. It might adversely affect trigger reach. However, a few of our females with small hands still found their 3913's to fit fine in
their hands. It's a case-by-case determination, though.
Do you have any suggestions for ammo? Keep in mind that the purpose of this pistol is to be her EDC. She needs to find ammo that she can practice with reliably and then find ammo that she can be comfortable enough to trust her life with...
Have you tried any of the 147gr JHP's? Maybe even the 124gr Gold Dot or Golden Sabre (either the standard pressure loads or the +P versions of either). Sometimes a slightly higher pressure round, which can produce a bit more slide velocity, might help mitigate a minor grip stability issue ... but the downside might be a little more felt recoil. Just depends on the shooter. Felt recoil is a
really subjective thing.
The shooter-related influence, being the grip technique and how well the shooter can hold the frame stable during recoil, can often be the most common cause of issues like this, though. It's not that the shooter needs to hold the gun in a "death grip" (a nicely consistently firm handshake grip seems to work for most folks), but keeping the wrist locked behind the grip is important.
If the wrist "breaks" either side-to-side (trying to angle the strong-hand wrist to "center" the gun in front of the shooter), or up-and-down (angling/bending the wrist to "lift" the gun up into the sight plane without raising the arm so the shooter's forearm is behind - and supporting - the wrist/grip) ... grip stability issues might result. Depends on the shooter.
Locking the wrist so the forearm is straight behind it, and then adopting a slightly "forward" stance (leaning the upper body somewhat forward, and NOT allowing the upper body/shoulders to lean backward under recoil) can usually help a number of folks when it comes to supporting the gun during recoil.
If someone doesn't maintain "follow-through" on their grip through their trigger press (versus holding on and then suddenly slightly relaxing as they think the gun is about to fire), then the frame might not remain firmly positioned and stable so the slide can travel fully rearward, at its intended and proper velocity ... and then return forward, under the intended spring tension, stripping a round from the magazine, feeding it into the chamber and then allowing the slide & barrel to continue forward and lock into battery.
A grip which is neither firm enough, nor supported by a locked wrist/forearm to the degree necessary, can sometimes "rob" the recoil spring of its ability to work as intended in feeding, chambering and locking up into battery. To put it simply, it can throw off the feeding timing.
Naturally, some attention to enhancing some grip & forearm strength is helpful to a lot of folks, regardless of their gender.
It's not possible to diagnose and give any sort of a definitive answer to theses sorts of things online. It really requires being present to observe a shooter to see the totality of what's happening with the particular shooter/gun/ammo combination. Sorry.
Just my thoughts in general, based upon what I've experienced and observed with other shooters as an instructor over the years.
Wish I could help, but I can't pretend to give you the "definitive answer" to your questions via an online discussion.
If I could, I'd have requested being able to "telecommute" when working as an instructor (safer, at times

) ... except when
I wanted to put in some trigger time, of course.

).