\documentclass{report}
\usepackage{mwe}
\usepackage{capt-of}
\usepackage{hyperref}
\usepackage{cleveref}
\begin{document}
\Cref{main,mainA,supp} given on following pages \textendash\ \\[4pt]
\cpageref{main,mainA} and \cpageref{supp}%see below
%Now comes the troublemaker \cpageref{main,mainA,supp}
\captionof{figure}{First SUB-FLOAT}
\label{mainA}
\cleardoublepage
\captionof{figure}{First SUB-FLOAT}
\label{main}
\blindtext[20]
\cleardoublepage%This is absolutely correct ;-)
{ % begin group