Bubbles after priming could be the backing paper on the drywall that is highly absorbent, can cause primer bubbles when water-based primers get it wet. Sometimes latex patching compounds can cause the same bubbling.
For example, a customer had a crack in a ceiling that he filled with joint compound and tape. When he primed the repair area, it bubbled. He let the area dry, sanded the bubbles and painted the area. It bubbled again. The problem only happened in a couple of areas.
First cut the bubbles with a utility knife and remove any loose paper and patching compound. Then tap the area with a small putty knife and check for any other hidden bubbles and cut them out.
Sand the area to knock down any loose material and prime with GARDZ primer by Zinsser. It will penetrate and seal the porous material providing a sound surface to finish the repair. If any blisters develop while applying the GARDZ cut them out and apply the primer to seal the area.
GARDZ should dry to a uniform sheen. If any areas appear dull it indicates a porous area and should get a second coat.
Once the primer is dry, you can re-patch the area with the compound of choice.
When the patching is finished and sanded apply a final coat of GARDZ before painting. No other priming is required.
I recommend taking a damp sponge with a little compound on it and tapping the area to emulate the appearance of many coats of paint. This will camouflage your repair so it does not stand out as a perfectly smooth area in a textured wall.