Oh boy do I understand your OCD pain here mate!!!
Bloody hell, my first Mavic Pro was absolutely brilliant, I loved it to pieces but it was plagued with the dreaded black frames camera flaw.
When I replace it for the second one, I could have cried when I found out there was no way to increase the camera filename numbers 
Know what I did?
I sat in the kitchen, changed the camera mode to take 5x photos at a time (mode name escapes me) and I literally sat there and took three hundred plus photos of the wall, to bump the filenames up
You can imagine the tears (and the expletives) when that drone also had to be replaced a few months later for my third Mavic 
Anyway!
You mean the cached ones?
I can’t remember, are you Android or iOS?
Have you tried a different device to determine if the problem is on the drone end of things or the device end?