If you search for longer and find more and more evidence for a bear in the area, and no evidence for a Yeti... then you can start saying "this is evidence that the 'yeti' was a bear all along..."
That's exactly how I read the OP. "This is evidence that the (thing that is referred to in legends as the) yeti is (actually) a bear (instead)".
Maybe it's the amount of evidence found?
Well, what counts? Does the eye-witness report of a large upright mammal roaming the Himalayas count?
I'd say so. Its not good evidence but its something to work with. It at least points us in a direction.
And if you then find bear fur in the areas of the reports, then I think that can lead us towards a working hypothesis that the thing that was seen, called the yeti, is actually a bear instead.
There is, however, something wrong with getting stuck on the 'yeti' aspect. At some point, that needs to be dropped or you're not following the evidence.
I suppose it depends on what you're trying to do.
If you're trying to figure out what the legends of the yeti stem from, then I wouldn't have a problem with keeping your hypothesis framed around that word.
If you're just trying to find a large mammal in the area, then there's really no reason to bring up the yeti in the first place.
Building something is a bit different.
You would 'drop the yeti' part by dropping any further development down a certain avenue if you identified that it was taking you away from your design goal.
Heh, sometimes the people paying the bills really really want their idea to come to fruition... and they might tell you to keep trying.
You would then attempt to 'find the yeti' again by trying something else (possibly new). And you'd be doing testing to see how close you're getting (this would be 'finding unique evidence of the yeti').
And often we have to tell them: Honestly, you just can't get there from here. We need to start a new route.
They don't like to hear that. lol, I've actually had a customer tell me to "work some magic"... I literally told them that there's no such thing as magic in chemistry. This was a grown-ass man. Desire sometimes outweighs realism.
Ah, but now I'm just rambling...