I dragged corners on a 18x24 for two hours last month because I kept telling myself the blur was just my screen. Exported it nine times. Nine. My kid walked by, looked at my laptop, and asked why I was playing with the blue dots instead of typing the numbers. Couldn't even be mad because he was right. Setting the size first takes ten seconds and saves you a whole afternoon of squinting at fuzzy text.

The network cable being the culprit is a solid find, but I'd push back a little on the interference angle. A staple through a cat5 or cat6 usually doesn't radiate enough to trip a zone on its own, even running parallel. What more likely happened is the staple nicked the jacket and shorted something, or the two cables were sharing a staple and the panel was seeing a ground reference issue through the shield. Zone faults that come and go with a wiggle test are usually a bad splice or a loose terminal somewhere in the run, not RF. I'd still check your zone 7 terminations before you call it closed, because if it was really just interference it'll probably come back the next time the AC kicks on.