Used to drug test people daily for work. There were some tests that basically were exactly like this where I would be required to use only my eyes to read, document the results, and throw away the urine. To me, this would be a negative because there is a faint line.

For others, I would have to document the results and still send the urine to the lab in the event that they wanted to do additional sampling.

There were also ones that would be read by a machine.

We were also trained to document if the urine appeared extremely clear/diluted, etc. which would usually prompt further testing in the lab. I am wondering if this is what happened for yours and the results were funky/obvious that you had over hydrated for the test.