Transact to MY.transfer errored: VM error: invalid opcode. invalid opcode The execution might have thrown

Hi, if you’re new to this you should follow the tutorial at
OpenZeppelin Upgrades: Step by Step Tutorial for Hardhat.

to get a basic understanding and a working environment.

It will guide you through a test and a deployment.

If you understand that, can you link your testnet contract? I would say something is going wrong with your dev environment.