The phrase "a clear exception is" is correct and usable in written English.
It can be used when you want to highlight a specific case that does not follow the general rule or pattern being discussed.
Example: "In most cases, the policy applies uniformly; however, a clear exception is made for emergency situations."
Alternatives: "a notable exception is" or "an obvious exception is".
A clear exception is Medicare.
A clear exception is the subset for Kyushu, in which the tremor duration is anomalously short with respect to the recurrence interval.
A clear exception is the minimized KAP-β system found in nematodes, as Caenorhabditis elegans appears to have ∼50% of the KAP-βs from the IMB1 clade.
A clear exception is the B biotype [sometimes also referred to as Bemisia argentifolii (Bellows & Perring)] which in the past 20 years has spread rapidly around the world to become a major crop pest in tropical and subtropical regions [17], [20] [23].
A clear exception is the most likely recent duplication found for the lexA paralogs of Xanthomonas, but this seems to be an unusual example.
However, a clear exception are models exhibiting oscillatory behaviour, or models with many non-observable states.
A clear exception was homoeologue 7C in which no kinship was found even though this LG had very high levels of homozygosity for both parents.
In general, the data suggest that a low lignin content in the plants favors plant bending during growth, with a clear exception being clone 89, which displayed moderate (level 2) plant bending even though it contained a very low lignin concentration.
The data indicated that carbohydrates comprised only small amounts of the extractives (Table 2), whereas the aromatic fraction made up approximately half of the extractives fraction for most of the samples, with a clear exception being clone 89, in which aromatics comprised only 14% of the total extractives.
The clear exception is yeast, a single-cell fungus that does senesce and that researchers use as a model to study aging.
The right and left don't seem to align on much these days -- especially in an election year -- but one clear exception is the need to address our criminal justice system.
