public key generated when importing PK different from original pub key
There are several different types of bitcoin addresses, which can be derived from the same private key. You can see this question for some more info about the different types.

So it sounds like your bitcoin-core wallet is creating P2SH-P2WPKH addresses, but then when you imported it into other wallets, they are deriving a P2PKH address. 

So the fix is to instruct the wallet that you are importing the address to, to derive the correct address type. Not every wallet will be able to do this, but some of the more feature-rich options out there should be able to do so.