Steam Harlem Line M3a Not Suppressing A Penalty Brake Application Where Due

While operating a timetable service with the MNCR M3A, I noticed that, while the "Overspeed" light is on and I put the combined power handle into the braking zone enough to where the "BA" light (green light) lights up, the "Overspeed" alarm and subsequent penalty brake application aren't suppressed like before.

It seems like the only way to solve this is to let the penalty brake application occur for a bit, then with the "BA" light on, acknowledge, then a running release will be performed.