ACF blocks/overrides coreStyles_ behaviour on paste

[Jakub Ś]

To reproduce:

1. Use below code for editor

   	CKEDITOR.replace( 'editor1', {
   				coreStyles_bold : { element : 'b', overrides : 'strong' },
   				allowedContent : true
   		});	
   

2. try to paste HTML containing strong tag (you can paste sample text from other editor, even other browser)

Result: strong tag is left untouched on paste.

While coreStyles_ work well with initial content and when button e.g Bold is pressed (B tag is inserted) they fail when content with strong tag gets pasted.
Please also note if you remove allowedContent : true property all works as expected.

Problem can be reproduced from CKEditor 4.1.