Over the weekend I tried bleeding my brakes but accidentally let the reservoir run dry for a bit. After bleeding the master cylinder and the caliper I messed up on, my brakes are firm again but i hear a "thunking" sound on press down.

Is this a normal sound or am I paranoid? The only thing I can think of at this point is to keep bleeding the calipers and try to get as much of the air out as possible.

Thanks in advance

(headphones can hear the thunk better)
https://imgur.com/a/Pz6Xl1T