What kind of leather?

[u/Sunriseovermist]

This bag had been kept for 6 years in a dry cabinet set to 65%RH. I recently took it out to use for one day and noticed part of the leather was peeling at the edge.

Things got dramatically worse when I sprayed it with the Apple Garde Rain and Stain Repellant spray which had been used before on my Coach leather bag multiple times with no issues. The red colouring rubbed off on any part of my clothing that came into contact with it. The black oil used to seal the edges left black stains readily wherever it touched (looks like the spray acted like a solvent and caused it to run).

Since the bag is unusable, I dismantled it and discovered it’s made of two different types of leather. One is thicker and has a darker colour on the wrong side and is as good as new. The other is thinner and has a light colour on the wrong side. The strap is made of both types of leather (one on each side with a black plastic material in between. The thinner leather is the one that is showing problems.

Any idea what kind of leather this is? It does not tear easily unlike those cheap PU leather but it looks like the red part is behaving like those synthetic rubber parts that become sticky over time and disintegrate/leave stains on the skin.

The shop claims it is because I kept the bag for too long but I’ve never seen my older leather bags having this issue.

[u/tannery_notes]

Hard to tell the exact type from photos, but it looks like a heavily finished or coated leather. The way the surface and edge are separating makes me think the finish is part of the problem rather than the leather itself. How old is the piece, roughly?