Not consistently clean, I am betting.
IMO, there's so such thing as a consistently clean UR jump. But in this case, the problem is that they are consistently landed UR jumps, that I suppose would be clean otherwise.
If a skater needs an extra 1/2 of a rotation for their attempt at a Triple to be ratified, then it's not even an underrotated Triple. It is just an overrotated Double.
An underrotated Triple = missing 1/4 of rotation at most from what is considered to be a ratifiable Triple.
I mean 1/2 rotation from landing completely backwards. This 1/2-1/3 of a rotation includes the 1/4 rotation that is allowed for a jump to be ratified as a completely rotated triple, so I guess it's really just that extra 1/4 rotation that the skaters can have the most trouble with.