USB PCB weird behaviour

Hi there, i was wondering if anyone could help me with this. I recently made a PCB for a FT2232H USB-serial converter in order to get an easy way of exchanging data between a PC and a microcontroller system. I followed most guidelines from FTDI to use their serial converter but my PCB has the following issue:

-USB device connects and disconnects repeatedly, unless i keep the PCB held in a certain manner.
-does stay connected if i use a male/female USB extension, running PC and MCU apps no problem.

I hand soldered my SMD PCB by myself using hot air, so plan on soldering another one to make sure it is not a soldering problem and i believe there is 50% chance the problem is there.

In the meantime, i am trying to check for other potential issues that can be causing this, maybe something about USB that i didn't know. Does anyone have any obvious gotchas i might have skipped?

I will provide all the necessary files if needed.

I had issues in the past with high speed USB products that didn't work with some USB cables, although the cables weren't particularly bad. It was rather a PCB design issue with the high speed traces.