how responsibility switch automatically by the system ?

hi Gurus

when you open any workflow approval page from work list (homepage) directly; and try to view any details, system switch responsibility automatically sometimes (if the function is not available in current responsibility. of course no responsibility context is set when you open workflow item from work list).

on what basis system picks the responsibility ?. i am asking this question because it is not same responsibility all the time. when system picks/switches incorrect responsibility we encounter issue and system throws page error.