Here is an expression e for which radcan(radcan(e)) # radcan(e). I'd
call this a bug:
(%i391) ((-x-1)^(-bb-aa-2)*(x+2)^aa)/(((x+2)/(x+1))^aa*(1/(x+1)-(x+2)/(x
+1)^2)*(1-(x+2)/(x+1))^bb);
(%o391) ((-x-1)^(-bb-aa-2)*(x+2)^aa)/(((x+2)/(x+1))^aa*(1/(x+1)-(x+2)/(x
+1)^2)*(1-(x+2)/(x+1))^bb)
(%i392) radcan(%);
(%o392) -(x+1)^aa/(-x-1)^aa
(%i393) radcan(%);
(%o393) -1/(-1)^aa
Barton