"Doubling in the upper left of the crown and the top of the vertical line, with marks in CANADA, P, and E and in ONE CENT"
Marler seems to have seen this stamp as a "Typical" Admiral Re-entry and afforded it no special attention.
Thanks to some great Philatelic Detective work by Randall W. Van Someren, it is now accepted as the only instance in Canadian Philately of a "Double Transfer - One Inverted".
Reported in The Admiral's Log Vol. XIV, No. 1 June 2018 and is nicely detailed on Ralph Trimble's Re-entry Site. The link below (will open a new tab)
R. Trimble's Page for 26UR6