The phrase "a second instance of" is correct and usable in written English.
It can be used when referring to a subsequent occurrence or example of something that has already been mentioned.
Example: "This is a second instance of the same error appearing in the report."
Alternatives: "another occurrence of" or "a subsequent example of".
The molecular conformation (a 75 triple helix) and hydrogen bonding schemes are similar to those previously reported for collagen triple helices and provides a second instance of water mediated N H⋯OC interchain hydrogen bonds for the amide group of the residue following Gly.
We extend our previous work by examining a second instance of co-evolutionary dynamics on Twitter, namely the possibility of an unfollow event to occur.
In cases where a second instance of a phenotypically defined gene occurs, an allelism or complementation test will be considered essential evidence.
If a second instance of a similar unmapped sequenced gene occurs, the best reciprocal match approach should be applied to rigorously confirm whether it is, in fact, the same as the gene previously identified.
Finally, we briefly consider a second instance of co-evolutionary dynamics on Twitter, namely the possibility that a user removes a follower link after receiving a tweet or retweet from the corresponding followee.
For his service in the Senate liaison office, McCain was awarded a second instance of the Legion of Merit.
It would be a first instance of the United States designating a unit of another government's military as a terrorist group.
Horky again applies an original approach and starts by detecting a first instance of mathematical Pythagoreanism in the Cratylus (chapter 4, 125 66).
A first instance of integrability without the Painlevé property was the derivation of the integrable system described by the Hamiltonian [21]: (2.1).
