I am reading 4.38V across all lines and between leds, everywhere I poke. I don't quite understand what you mean by the resistance of the power and ground lines, I measured the resistance between the 5V and GND with everything powered off and it gave me 512 ohm (if I'm reading this right hahaha).
Nice to know there is someone else that also thinks it's a hardware issue, I'll make a test and just re-wire that faulty line 3 over there.
EDIT: I tested a different part of the led strip, wiring it to the third row and the colors were matching perfectly. It was indeed a section of the strip malfunctioning. Luckly for me, I didn't use the whole strip on this matrix, I still have some leds to spare.