One of my keyboard switches doesn't respond half of the time, please help!

[fortissim2]

Hey everyone,
I've finished my Corne build but for some reason my C key barely works! It seems to trigger at random times when I press it down, but most of the time when I press it normally it just won't register.
Sometimes it seems to work just fine when I'm typing or playing, but then in the middle of a sentence it would just stop working entirely. In some cases, the keypress would register with some small latency, and in some rare cases, the key will register like 2-3 times when pressed once!

Things I've tried:
- replacing the keyswitch (I use Akko CS Lavenders)
- replacing the Kailh hot-swap socket
- removing the keycap and pressing it on its own (still the same result)
- restarting my computer and re-flashing the microcontroller (Arduino pro micro w/ USB-C)

I'm REALLY desperate for a fix because I can't find any information that could help me, and I really don't want to buy new switches since shipping is pretty costly in where I live.
Thank you!

[suicidal_orange]

Have you tried touching a wire between the two contacts of the hotswap socket and seeing if that types reliably?  Could be a cracked trace from that socket to the next socket or to the diode and pressing harder or slightly off centre bends the PCB making it work sometimes.

[fortissim2]

Have you tried touching a wire between the two contacts of the hotswap socket and seeing if that types reliably?  Could be a cracked trace from that socket to the next socket or to the diode and pressing harder or slightly off centre bends the PCB making it work sometimes.

I have tried shorting the hotswap socket and it seems to work fine both times (first with the old hotswap socket and second with a new socket).

[suicidal_orange]

If you're confident that the shorting is reliable that leaves only one thing that can be the problem - the diode.  Hopefully the kit came with a couple of spares so swap it out it should be good.

[fortissim2]

I've done that once but I'll try it again, third time's the charm

And while typing this I was slamming my C key and when it finally registered, it registered like 10 or so times. Why is keyboard building so janky