Solved I Have An Unreliable Thunderbolt Port The Second One Works Fine Macbook Pro 13 Two Thunderbolt Ports Late 2020

Chosen Solution

What could be the issue? The first one works then stops, then works then stops, I noticed some corrosion on the board while replacing the trackpad, but it’s very confusing. None of them seem to even affect the tb3 controller.

You may need to replace the MacBook Pro (A1989, A1990, A2141, A2159, A2251, A2289, A2338 Mid 2018-2022) USB-C Board that will require lifting the logic board out to give you access to the screws which hold the port assembly as you can see here