If your nail polish bubbles this can have different reasons. This is what I have observed about my own nails.
Back in the olden days I used to have a lot of bubbles in my nails every time I used nail polish. I applied very thin coats and let them dry a long time and it didn't change a thing.
Then I had a moment of d'oh. My nails were very brittle and the top layer was cracked lengthwise. And most of the bubbles were aligned along those cracks. When my nails got healthier and stayed intact, most of the bubbles vanished.
Now I only get bubbles if I skip my first base coat, a shiny treatment, and only apply a sticky base or ridge filler. Another factor is whether my nails are damp, these days I either wait a few minutes after washing my hands or I use the smoothest side of a nail buffer to speed up evaporation.
Do you get bubbles in your polish? Did you get rid of them?