Which epoxy and fiberglass you used? It could be surface problems or simply not a proper glassing technique, since you dont sell kayaks to others, its not your job, then just think about it as: it happens, will go better next time, just follow the instruction like you never seen fg before and leave the forensics (they are useful only if you really know all your steps, not for maybes).

Someone might give you better suggestions but from my experience, i would first want to be sure that once fixed it stays fixed. So i would probably cut a little corner close to the edge of the delaminated area and pull that corner to see if the glass holds well or tends to come off past the edges. You said that those same spots were smaller before, i wouldnt want a patching session every year.

If im confident that the delamination wont extend, would avoid cutting and patching, simply for the little more work involved, id flush with acetone: two siringes one to inject it and one on the opposite side to suck it out, being really careful to clean the edges, (i dont have problems with acetone not being pure and leaving residues) and then inject the resin under the delamination like you did with the smaller bubbles you said you already fixed. The acetone should be able to soften the resin in the delaminated glass so it stays put, if worried that it lifts you can do a local vacuum patch or use a bag of sand or water balloon or simply a wrap with some saran wrap.
That is quick, but has the nastiness of the acetone and theres the possibility that if not done properly comes out not a sound fix. If you are worried about that then the only other thing is to cut off and patch.

: I stored my kayak for the winter this past September, and sometime around
: Christmas, I noticed the fiberglass delamination shown in the attached
: pictures. Some of it was present on my last couple of paddling excursions
: last year, but the areas have drastically increased in size since.

: How to fix? What could have caused it?

: I don't think that I used the most pristine methods of keeping my mixing cups
: clean, didn't scrub a whole ton of blush, but why in these localized
: areas? The fact that the delam goes across my hatch rim (see next post for
: highlighted pictures) leads me to believe that it was some kind of
: localized contamination. I wonder if I leaned up against the hull
: (pre-glassed) with my forearm and left a greasy, sweaty spot? I wiped w/
: acetone before glassing, but maybe I didn't wipe enough?

: I had small spots like this just after glassing, but they were always small -
: 2 to 3" in diameter. I filled these w/ epoxy using a syringe. I'm not
: sure how to fix these much larger spots. The top one is about 1' x
: 4". The bottom one is about 3" dia. on the hatch, and 8" x
: 3" on the hull next to it.

: Any help would be greatly appreciated!