Kenmore Model 106.8670380 water in bottom of fridge

Brand:Kenmore
Model Number:106.8670380
Main Symptom:Found water leaking down back inside of fridge
What happens & when: see ice at top where the cold air comes into the fridge portion of the unit.

Error Code (if any):
Parts or tests already tried:
Photos / video link:

My wife says that she every now and again she is finding a small puddle of water on the lowest shelf. I looked and can see an small ice build up in the fridge at the top where the cold air comes into the fridge with wetness down the inside back of the fridge from that point down. I checked the fridge (40degrees) and freezer (0 degrees) operating temps and they are correct. I removed the back panel inside panel of the freezer and I could find nothing there, was thinking maybe when the fridge does it auto defrost maybe there is a crack in the drain tray that is letting the water leak below? Did not see anything and pouring water into the tray did not result in any entering the fridge.
We purchased the fridge new in 1986 and I have cleaned the coils and fridge every 3 months. Up till now its been trouble free.
Additional info on fridge
Kenmore Model 106.8670380 with no ice maker or water feature.

It might be possible that the diffuser or the diffuser gasket could be degraded, or the refrigerator gasket could have a small air leak. Have you noticed any moisture closer to the door at all?

Thanks for the reply, no moisture near the door. The door seal is newer as I replaced it 4yrs ago. I was able remove the diffuser cover inside the fridge to get a better look at the diffuser but have not so far discovered how to remove the actual diffuser assemble to inspect the gasket. Using a mirror I could not find any screws from inside the fridge holding it on and removing the back panel in the freezer did not reveal any screws going down to hold the diffuser in place from above.

Do you notice any cold liquid coming from behind the diffuser insulation? Or does it seem to be coming more from the drain cup? Removing the cover should have both exposed to be able to identify the specific area the liquid is coming from.

The ice build up is just behind the diffuser by the corner nearest the cup. I took a photo but can not figure a way to upload it to here.

Are you able to provide a link to the picture using something like imgur or google? This could very well be a case of a clogged defrost drain that is leaking out where the cup is.

Ok finally figured out how to do the photo. I tried to make a red box around where the ice is forming and dripping down. I had already checked the drain hose that attaches that cup in the back. I still have not figured out how to remove that diffuser. Just can not find any screws anywhere to check the seal between it and the fridge.

If there is not a screw on the back right side of the diffuser, does the plastic cap in the center back of the diffuser pop out?

Thanks for the reply, I will have to move things out to check into how the cup is installed. I did not see any screw in the back of the diffuser. I am in the middle of residing the house with trying to get it done by Sunday with working evenings after work and this weekend so it might be a bit before I get a chance again to look at the fridge.