How to import multi sig using importmulti correctly?
createmultisig is likely giving you the p2sh-segwit address, not the p2sh one. This means that the "redeemScript" you get from it is actually the witnessScript and the real redeemScript is the p2wsh script for your witnessScript. You can tell createmultisig to create just a p2sh address by setting the address type parameter to legacy.

Alternatively, you can get the redeemScript for your witnessScript by usingdecodescript.decodescript` will first decode your script, then it will give you the various possible addresses for it (for each address type available) along with the scripts for them.