Recent work on markedness has claimed that round vowels and dorsal consonants are never epenthesized. However, Seri seems to present exactly these types of epenthesis. Relevant data are presented and discussed, and it is claimed that these rules are valid counterexamples that need to be taken into consideration more seriously.
Marlett, Stephen A.
"Round vowel and dorsal consonant epenthesis in Seri,"
Work Papers of the Summer Institute of Linguistics, University of North Dakota Session: Vol. 50, Article 2.
Available at: https://commons.und.edu/sil-work-papers/vol50/iss1/2