I think he's referring to the two white 'brake pressure' needles on the triple indicator.
The needles are (normally) only active when you apply the Parking Brake. Using the Brake Pedals gives no indication on the needles in (normal operation).
Normal braking is powered by the Green hydraulic system, and when you set the Park Brake a shuttle valve moves across to switch the power source to the Blue hydraulic system.
If the shuttle valve sticks then the transfer will not occur. A symptom of this is that you will see an indication on the pressure indicators when you actually shouldn't. This is why you look for a drop in the needles before taxi out after engine start (feet on brakes, park brake off).
Therefore, in your scenario, if you are using the Brake Pedals and see an indication on the triple indicator, then what appears to have happened is the shuttle valve has not transferred the source to the Green system - so you are braking on Blue.
You may have had a BSCU failure.
If it was anything else (Green hydraulic failure?) I'd expect ECAM warnings which you haven't mentioned.
If you are not moving or touching the pedals and the indictors suddenly show pressure then you would appear to have the brakes on in Blue. I've heard of an Airbus have this happen and they couldn't get the brakes to release. They were stuck at the hold for half an hour - caused major disruption.
In the first scenario, I'd go back for maintenance investigation, and I'd taxi slowly, being gentle on the brakes, and making sure we have at least got good Blue Hydraulics before going on stand. Get chocked ASAP.
In the second scenario I'd choose a tow-in.
Did I pass????