I made a transaction where I used bitcoin core's segwit addresses. There were 2 inputs, both segwit addresses (with a total balance of 2.5).
I used sendmany and sent to 3 outputs (1 segwit and 2 legacy addresses) a total of about 1.95. The strange thing is that the change of about 0.55 came back to a non segwit address to my wallet (address starting with 1).

My question is: is this normal? I assume that if I send from a segwit address, the change should also come back to a segwit address. Wrong?

The 2nd question is about fees. Before transaction, I set a fee of 0.0045. bitcoin-cli settxfee 0.0045
Yet, when I check the transaction on blockchain.info it states that I only have: Fee per byte 301.537 sat/B.
So, basically I set 450 sat/B but when I sent out, the fee used was only 301 sat/B. Why is that?

Does this have anything to do with the weight?

I see this:
Size    488 (bytes)
Weight    1304

Why did it set a lower sat/B fee than what I set?

Your comments are appreciated.