Is Pulla often pronounced Bulla? Kiitos!
If you mean the Finnish word pulla (‘bun, coffeebread’), I think it can be pronounced as ‘bulla’ only if you have a flu or rarely in some Finnish dialects. According to Kielitoimiston sanakirja, the Finnish word bulla means also ‘papal bull’ - https://en.wikipedia.org/wiki/Papal_bull.
Finnish pronunciation does not make any great difference between b and p (in fact, b does not exist in the language), so p may sound b, it depends... and vice versa.