chain.mine with timedelta not working on Hardhat

[EdNoepel]

Environment information

• brownie Version: 1.18.1
• ganache-cli Version: 0.1.5
• solc Version: 0.8.0
• Python Version: 3.8.10
• OS: linux

What was wrong?

Calls to chain.mine which specify a timedelta do not work when using hardhat as network. Specifically, upon submitting a subsequent transaction, a RPCRequestError is raised stating the next block timestamp is lower than the previous block timestamp.

How can it be fixed?

I have not delved into the eth-brownie source, but I put together a sample project to consistently reproduce the behavior: https://github.com/EdNoepel/brownie-test-issues/blob/master/tests/test_mining.py

[EdNoepel]

Possibly relevant: https://github.com/eth-brownie/brownie/issues/709