We correct a mistake in a lemma in the paper cited in the title and show that it did not affect any of the other results of the paper. To this end, we prove results on linearly disjoint field extensions that do not seem to be commonly known. We give an example to show that a separability assumption in one of these results cannot be dropped (doing so had led to the mistake). Further, we discuss recent generalizations of the original classification of defect extensions.
"Correction and notes to the paper “A classification of Artin–Schreier defect extensions and characterizations of defectless fields”." Illinois J. Math. 63 (3) 463 - 468, October 2019. https://doi.org/10.1215/00192082-7902469