Pretty widely understood at my last two companies to mean something like “looking into this” or “taking a look.” Basically just a quick acknowledgment to let the person asking the question know that they can probably expect a response from that person soon, and lets others know that someone’s already on it so we don’t duplicate effort.
I always assumed this was a common usage on Slack.
The League of Legends launcher used it at one point. Not sure if it still does.