UPDATE -- please see my last post in this thread. This was caused by some confusion on my part about keys.

When creating a multi signature 2 of 3 wallet using a combination of xprv and xpub keys, it appears that the addresses created by Electrum (v 3.2.3) depend on the particular combination of keys used. For example, say there are 3 keys, A, B, and C.

Wallet 1: One creates a view only 2 of 3 multisig wallet using the 3 xpub keys, xpub A, xpub B, xpub C.

Wallet 2: create a new wallet using 2 of the 3 private keys. If one uses xprv A, xprv B and xpub C, the same addresses are produced as Wallet 1.

Wallet 3: create a new wallet using a different set of 2 of the 3 private keys, say xpub A, xprv B, and xprv C. This wallet now has a different set of addresses.

This does not seem correct. Any ideas on the problem or what algorithm Electrum is using?