The phrase "a puzzling aspect" is correct and usable in written English.
It can be used when discussing a particular feature or element of a topic that is confusing or difficult to understand.
Example: "One puzzling aspect of the theory is how it accounts for the observed anomalies in the data."
Alternatives: "a confusing element" or "a perplexing feature."
Kessler points to a puzzling aspect of Rice's record.
Now we are on this subject of sex, I am keen to resolve a puzzling aspect of all this.
To the Editor: Paul Kengor doesn't come to terms with a puzzling aspect of the president's foreign policy: Which of two very different philosophies is guiding this president?
Both reflect a puzzling aspect of Brown's career that combines high-minded intent, a very real desire to serve the public good, with a fatal streak of insecurity.
However, the tsunami quantification is still a puzzling aspect in the tsunami research since the several scales proposed to measure tsunami size often either are confusing as for the quantity they represent, that is intensity or magnitude, or lie under serious difficulty in their applicability.
And it points to a puzzling aspect of Don't Ask Don't Tell: Why would we want soldiers, who might some day be generals with a voice in policy (and they often do have one), to keep secrets that could destroy their careers?
A most puzzling aspect of the epidemic is the low rate of infection among health workers who cared for SARS patients in China, Dr. Stöhr said.
A final puzzling aspect of the mitochondrial results is the anomalous patterns shown by the Euarchontoglires – the group that contains both rodents and primates, and so all of the most highly studied mammalian models.
For social scientists, it's an object of research, offering clues to a fundamental and puzzling aspect of human nature: People need to belong, to feel a part of "us".
From a US perspective, the puzzling aspect of UK Uncut's focus on finding alternatives to austerity is its resemblance to the current Republican party line.
There are a few puzzling aspects of the results, especially with regards to the specificity of value (DVcur-DVave) representations in the brain for different contexts and choice types.
