Time.increase() bug

truffle version:
Truffle v5.5.11 (core: 5.5.11)
Ganache v^7.0.4
Solidity - 0.8.13 (solc-js)
Node v16.14.2
Web3.js v1.5.3

I'm using time.increase(seconds) to increase time ( = block time in ganache config) to test some function using block.timestamp in my contract.
In my contract i have a function to get block.timestamp.
First I make an eth call to check current block.timestamp from my contract (t)
After using time.increase(blockTime), I make another eth call to check block.timestamp again.
return value should be t+blockTime and my test will success.
But sometimes the return value is t+1+blockTime make my test failed.
I think it's truffle or ganache problem but don't know how to fix it.
Thank for any advice

Hi, welcome to the community! :wave:

I am not sure for this, maybe you can ask the Truffle team for help directly, such as having a check on their repo