[Help] Switch Hitter - test on PCB shows chatter?

[Menuhin]

I am such a newbie in projects, so I use the Switch Hitter from elitekeyboard to test out a PCB with a pair of tweezers.
And Switch Hitter gives consistently chattering alert (red) to a single key, and consistently green to all other keys.

If I understand correctly, key chatter should be related to switches and I have no idea what it means when it says consistently a key placement has chatter when tested with a pair of tweezers - on a PCB with not a single key installed.

Well, am I overkilling it to use Switch Hitter to test a PCB? What do people normally use?

[Findecanor]

What is the firmware, and the location of that switch within the matrix?

Have you checked that the switch's diode does hot have a faulty solder joint?

[Menuhin]

What is the firmware, and the location of that switch within the matrix?

Have you checked that the switch's diode does hot have a faulty solder joint?

That's a KBD75 and the key is the Tab key, with no switch soldered.
The diode seems to be correctly soldered at the back.

When I tried it with a switch connected using Holtite hotswap sockets, there appears to be no chattering error on Switch Hitter on that key. Of course, it then means fine, but it further puzzled me...

[Muirium]

Chatter shouldn’t be a problem with no switches installed. Seems more likely you’re picking up noise than useful signal. Onward with the build!