I have a circa 1950, "Smith Miller Mobil Tanker" truck. Here's are "before" photos of the truck: https://www.etsy.com/listing/6039193...s-truck-tanker

I have:

used a paint-stripper to remove the original paint.
sanded the wooden body to a smooth surface.
applied an undercoat.
applied several coats of Rust-Oleum "Painters Touch" "Ultra Cover" Multi-Purpose Brush-On Premium Latex paint.
applied the decals.

The decals are now chipping off and there looks like air bubbles under the decals.

What did I do wrong?