We always blame the wrong thing first, that's just how it goes.

Cheap wand wins for tone and probe every time in old buildings. The fancy kit only earns its keep on big commercial runs where you need the probe to sniff out one pair in a 200 pair bundle. Crosstalk makes those pricey probes useless in apartments. You're not using it wrong, you just bought the right tool for the wrong job.

But what if it's not just normal erosion? Could be something else, like a small quake we didn't feel or the ground water shifting. Seen that happen before.