Where deft challenges plea at trial by asserting grounds of innocence, an appellate challenge to the plea on other grounds is reviewed for plain error.
No plain error in magistrate's acceptance of plea where deft made one or two word answers in colloquy and court did not inquire into possible bipolar disorder.
http://media.ca7.uscourts.gov/cgi-bin/rssExec.pl?Submit=Display&Path=Y2018/D06-13/C:17-1776:J:PerCuriam:aut:T:fnOp:N:2169817:S:0
Since 2011. An occasional commonplacing of the U.S. Circuit Courts of Appeal.
Neither an authoritative statement of the law nor legal advice. Quick work.