The A is not at the edge of the keyboard, so it's probably not the keycap rubbing against the edge of the case.
By the way, is this with the keycap on or off?
If on, please (carefully) remove the keycap and see how the switch feels without. Compare it to a couple of other adjacent switches.
It is possibly just something simple like the switch is slightly misaligned (especially if it is plate-mounted) and the keycap is rubbing against an adjacent keycap).