The key is "without authorization". You're allowed to fix things and add features, but deliberate sabotage is arguably unauthorized. You might win in court, but as others said elsewhere, court is Too Expensive even if you win.
That, and I wouldn't be surprised if they didn't go after you for industrial espionage or something.
Except that you're entirely authorized to access the computer system.
Purpose or intent isn't defined in that particular law.
Do you have authorized access? Well, as an employee you do.
This isn't a criminal matter, it's a civil one, and no company is going to sue a saboteur unless they need an example made; they stand to gain nothing.
A company doesn't get to retroactively redefine what "authorized access" is as it suits them.
You have authorized access, but the statute says 'cause unauthorized damage' (which in its most literal reading could be an unintentional bug, too - don't think for a moment I'm supportive of this).
That, and I wouldn't be surprised if they didn't go after you for industrial espionage or something.