Yes, you can. The feature is called Adaptive charging. It isn't all that new, but you probably received it in your last update or it has been enabled to be default then, if you haven't turned it on yourself. You can turn Adaptive charging off in Settings / System Preferences / Adaptive charging. You can type simply "adaptive charging" in the ChromeOS search to find the option quickly.

But, even if you don't turn it off, the battery is still capable of charging to 100%. The system just makes a guess when to delay full charging, based on your prior usage. I assume they want to avoid full charge in periods of the day when they predict your Chromebook will remain plugged in for long time. Like when you charge it overnight.