I have had the G2 since the day it came out and am now on cable 4. Three were replaced by HP FOC.
My lastest cable died this week (same occasional black flashes and occasional strange lines across the screen).
This cable lasted a lot longer as I used a loop system on top of the headset to protect the plug that goes into the headset (I found the info online).
I have just ordered a new spare (I always have two spares on my shelf, after a panic a while ago where there were no cables available to buy anywhere on the web).
I absolutely love the G2. With increased resolution thanks to OPENXR tools it looks fantastic.