Left joy-con connects wirelessly but isn't detected as on the console

Just like the title says, the joy-con connects wirelessly and seems to be charging while attached to the console, but the console doesn’t see it as *attached* to the console.

Recently swapped the housing w/ some ExtremeRate custom plates, so I assume I've nudged a ribbon or there's something loose hardware-wise, but everything looks fine as far as I can tell. Tried searching for the answer but could only find what I'd already tried. Hoping to find some hardware savvy help here, appreciate any help that y'all can provide!

Things I have tried that have not worked (but may work for someone else having the same issue):

• a different left joy-con connects seamlessly to my Switch and shows correctly as connected to the console
• tried putting my non-working joy-con on another Switch, but the issue persists
• I tried swapping out the rail with an extra rail I had lying around from another customization - still connects wirelessly, still not detected on the console
• System updates and controller updates have been done
• Disconnect by tapping sync button on joy-con and placing it into the system
• Disconnected and reconnected the ribbons for each tested rail and ensured the connections were tight
• Swapped the battery
• All connector pins are clean and unbent
• Went into System Settings -> Controllers and Sensors -> Disconnect Controllers while faulty joycon was on the Switch. Only one that reconnected was the right joycon which was already working fine
• Gave the joycon a small wiggle while on the Switch to see if mild pressure in different directions may initiate a connection - no luck