Dual Purpose breaker (Eaton type BR Combination AFCI/GFCI) trips when starting blender or vacuum
I believe your dual function breakers (GFCI and AFCI protection) are thinking you have an arc fault, not a ground fault or excessive current.  A "Combination Breaker" is one that provides series and parallel arc fault protection and not GFCI protection. Some people confuse "Combination" with GFCI and AFCI, but those are properly called "Dual Function", as you did. 

Is the bathroom outlet AFCI protected?  If not, you just ruled out over-current (inrush) and ground fault causing the trip, meaning the other breakers are thinking there is an arc fault.   

Motors that have brushes are common causes of what you are experiencing. Unfortunately all this great new "protection" is interfering with day to day operation.