PCBgogo

I have been chasing a bug for two days now and finally found it: on my test rig.
I was trying to diagnose a problem identified at another site. They sent me the device to check and I couldn't reproduce their error, but was noticing a different one. It seemed the whole board was bad (the assessment I was given was that it was an intermittent problem that indicated a cold solder joint or a cracked trace, so I was already planning to replace the whole board.) So I replaced the board ... and encountered exactly the same problem again. This was part of a circuit path that I had never previously tested, so I assumed it was a problem in the board design or some such thing. After poring over schematics and doing continuity tests, I eventually determined why I was getting the problem: I had a short where there should be no short. It didn't take long before I had the test jig detached and was debugging it. I had an inexplicable short which I thought might be due to some bodges, but upon tracing it, I found the problem: See "Before.jpg".
The copper pour had a manufacturing defect which attached it to a via. I don't mean to bash the PCB manufacturer because their service's primary function is cheap prototypes, so they omit testing. On our main boards, our manufacturer does full electronic testing which, I guess, would have handily caught this error and I never would have seen the board.
Scratching away with an X-acto, I cut the offending trace and fixed the problem: See "After.jpg".
I guess this is just a cautionary tale, but I'm not sure what to take away from it. The test rig I was using I had no problem with for 2 years, but since I was in a new circuit path, I encountered a problem I didn't expect.

I think it would behoove me to keep a notebook. I should write down what the expected result is, and what the measured result, marking all issues where the results were far astray, even if (especially if) it was only a momentary problem. While this would not have solved my problem, a more methodical approach may have led me to an answer quicker and with less frustration.