I believe that is the case for KM.
As our discussion indicates in the topic RegEx for Horizontal Whitespace (\s \h \t blank etc) there is considerable confusion about this.
My research today seems to show that [[:blank:]]
includes ONLY SPACE and TAB characters. IAC, there is no doubt about what \h
includes, so, IMO, it is the best choice in KM RegEx Actions to use for horizontal whitespace.
If you find a reference that indicates differently, please post in RegEx for Horizontal Whitespace (\s \h \t blank etc)