I've been involved in 3 way checks before. I've never been the third checker to return, but have a look at this SoB WU:
http://www.primegrid.com/workunit.php?wuid=417482969
After 4 checks returned the result is still inconclusive. I am the 5th checker!
I should return my Task in about 3 days.

Who will be knocked out, who will survive, find out next time on Total Drama Work Unit!

Of the four hosts whose results do not match, two have a history of invalid results, i.e., they're producing bad calculations (excessive overclocking, bad memory, etc.) A third host has no invalid tasks, but does have a second inconclusive task, so it's probably having problems too.

So of the four computers, two are almost certainly faulty, a third is likely to be faulty, and one computer is probably working correctly. Just coincidence that they all worked on the same task.
____________
My lucky number is 75898⁵²⁴²⁸⁸+1

55459*2^27802306+1 is not prime.
As suspected, Doc No returned a good result.
You can be my wingman anytime.

On a side note, it looks like SoB is getting to the 50,000 credit per WU mark.

I have one in pending that's reporting >63k credits.