ios - Cannot Save PFObject after updated ParseFacebookUtilsV4 -

i updated parsesdk 1.7.5 , parsefacebookutilsv4 (1.7.5)
our users can not save pfobject this.

pfobject* post  = [pfobject objectwithclassname:@"postdata"]; pfuser* user = [pfuser currentuser]; [post setobject:user forkey: @"user"]; ...  [post saveinbackgroundwithblock: ^(bool success, nserror *error){     if ( !success || error != nil ){         ....     } }]; 

it returns error "user objects cannot allow writes other users".
user using facebook login , siged in previous version's parse sdk (before facebook sdk 4.0).

even if user deleted app , re-installed, it's same error.
, never happens user signed after parsesdk 1.7.5.

login facebook, i'm doing this

[pffacebookutils logininbackgroundwithreadpermissions: @[ @"public_profile", @"user_friends", @"email" ] block:^(pfuser *user, nserror *error){ }]; 

when commented out adding user pfobject, succeeded.

please give me advice.
thanks.



note: quick fix, stopped adding user on client, , use cloudcode

parse.cloud.beforesave( "postdata", function(request, response) {     parse.cloud.usemasterkey();     var user = request.user;     var obj = request.object;     obj.set("user", user);     response.success(); }); 

it works...