Progressbar modifies outside object of max attribute

[MartinNuc]

Today we dealt with issue that in one objects in our app appeared value 100 which triggered our watch although data were not loaded from server yet. We tracked this to progressbar where property of this object was used in max attribute. Progressbar modified object provided in max attribute.

Here is plunker reproducing issue: http://embed.plnkr.co/m5f9yz/

Progress bar uses object loaded from the server to set value and max. However referenced object is modified by default parameter (100) of progress bar until data are loaded from server.

Expected behaviour: Object used in max attribute should not be modified. Progress bar should use internal value to represent current max value.