Yes. With continued prolonged use, the sunray probes do tend to develope frays in the chord. So for example, if it's just sitting there on the ground, with no problem, nice threshold, as long as you don't touch it. But the minute you pick up the probe, and wiggle it in the air (away from all metals) if it starts to chatter, then you may have a frayed line.
You might be able to isolate the point in the line where the fray is, by holding the line firm (pinched against the ground), while wiggling independent portions of the line. Find the portion where the stutter occurs. You might be able to cut that out, and resolder. But odds are, most of the time, the fray is right where the line enters the probe itself. Thus you can't cut and solder there.
The probe itself sometimes goes bag, like if it's accidentally banged it around over the years. To determine this, you might be able to hold it firmly on the ground, and tap along the sides of it with your finger (while holding the chord perfectly flat/still).
And yes, sometimes the problem is solved by lower sens. levels (ie.: going to auto-sens). But that's a hassle to keep having to go into auto, each time you switch to probe mode.
I've had to send several sunray probes in over the years. I might also add that the problem "sneaks up on you", because it starts subtly, and takes time to worsen. So sometimes you don't even notice the flutters because you subconsciously know the coin signal in the hole will be louder. But then one day you wake up, notice MAJOR stutters, and ask yourself "how have I been living with this and not notice it till now?"
