perlebcdic: Document v5.22 EBCDIC bugs

pod/perlebcdic.pod

@@ -1842,6 +1842,22 @@ XXX.
 
 =item *
 
+The C<cmp> (and hence C<sort>) operators do not necessarily give the
+correct results when both operands are UTF-EBCDIC encoded strings and
+there is a mixture of ASCII and/or control characters, along with other
+characters.
+
+=item *
+
+Ranges containing C<\N{...}> in the C<tr///> (and C<y///>)
+transliteration operators are treated differently than the equivalent
+ranges in regular expression pattersn.  They should, but don't, cause
+the values in the ranges to all be treated as Unicode code points, and
+not native ones.  (L<perlre/Version 8 Regular Expressions> gives
+details as to how it should work.)
+
+=item *
+
 Not all shells will allow multiple C<-e> string arguments to perl to
 be concatenated together properly as recipes in this document
 0, 2, 4, 5, and 6 might