just to make it clear, I mentioned give it a couple days because it is fresh filled, need a couple days to reach the room temperature, then you can test it again.
After two days if it is still around 1800psi, it should be fine because the cylinder and the regulator are both ok to handle the pressure, you don't need to the release the extra co2,(just avoid high temperature, more than likely not the case) but if you prefer to release, do it outside without regulator attached, slow and steady turn open/close the cylinder valve in intervals, avoid large flow of co2 in prolonged of time.
you can not release the large volume of co2 through the common pressure regulator, because the regulators to handle fast flow of co2 are special designed.
The valve seat inside the common pressure regulator will frozen and cracked if co2 rush out too fast.