Is it possible for two nodes to view blockchains differently?
Absolutely! This is why consensus is so important in Bitcoin. If there is a fork in the chain, a transaction could have 1 confirmation on one fork, and 3 on the other fork. Eventually one of these forks is going to win out and become the defacto blockchain. I don't think 3-4 confirmations would be common in Bitcoin, but if you are on an altcoin it definitely seems feasible. Testnet3, bitcoin's test network, routinely has these competing chains for short amounts of time -- after there is a clear winner the losing chain reorganizes on to the longest chain.