Strange Di2 connection port issue (that resolved itself)

[echappist]

I experienced a rather strange Di2 issue on a derailleur I recently purchased, and this issue somehow seemingly resolved itself despite being quite persistent when I first encountered it.

In short, when I first tried installing the derailleur and connecting a Di2 cable, I simply could not get a secure connection between the derailleur and the E-tube cable. The E-tube cable kinda "mushes" into the port, but there was neither the crisp aural nor tactile feedback associated with a proper connection. And the electronics front verified this as well: the derailleur shifts only when I physically ensured the E-tube cable was all the way in, but the electrical connection would be interrupted when I stopped applying force. I tried this with 5 different E-tube cables and used the Shimano installation tool each time, but to no avail.

Before I was about to return the derailleur, I wanted to give it one more shot. And for whatever very strange reason, I got the crisp aural and tactile feedback associated with a proper connection.

I'm now wondering what might have caused the issue I originally experienced. Has anyone encountered anything similar?

[rice rocket]

You know when your USB-C/lightning port gets lint in it and it stops charging unless you fiddle with the cable?

It's like that.

[echappist]

But I did absolutely zilch to the derailleur between the two attempts. That's why it's so weird.

[camelbackkid]

Things don't fix themselves!

https://www.youtube.com/watch?v=0B61_5sRoBI