scriptsig-not-pushonly (code 64) during send transaction in regtest I create a transaction in regtest without send it, I have transaction data signed.
I modified a little bit the scriptSig in order to replicate transaction malleability, I add two operations (2 OP_DROP) and increase the scriptSig length from 6A to 6C.

this is my final result.

0200000001b6a6018077d7e817c13074f4127a641a3225b44e56318ef61d2b746b0271e308000000006c527547304402205fa24c98406b9f18732a586a2d5a5cf8ed5e033afca89dda772963f87bff457d022020c796be2fd4c6c47733214293263e244828211a51f044872090e610d5e1e8820121024f29076388ac6ed18b281a149e88043be7e78f72e138f3498853d8918f7f5448ffffffff01606b042a010000001976a914f1edb261a91e7cb03737708d718b2c47b7aa5c8e88ac00000000


When I try to send rawtransaction I receive this message:

error code: -26
error message:
scriptsig-not-pushonly (code 64).


I'm using bitcoin-core 0.19.0.1
One of the standardness rules (relay rules) in Bitcoin Core is that the scriptSig must contain only operations that push data to the stack. Since you have actual opcodes that do non-push things, this transaction is non-standard so your node is not accepting it.

On regtest, you can disable standardness checks by adding -acceptnonstdtxn to your startup command.