Undefined property: stdClass::$uid in _fivestar_field_helper and module unremovable

The following error happens:
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Notice: Undefined property: stdClass::$uid in _fivestar_field_helper() (line 144 of /var/www/html/MYSITE/sites/all/modules/fivestar/includes/fivestar.field.inc).
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when trying to remove a fivestar field from a content type.

After that the module can not be removed in admin/modules: "Required by: Drupal (Fields pending deletion)" !

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Steps leading to error on my system:
Install d7.52 + Theme 'gratis' + Modules:
ctools
devel
file_entity
fivestar
libraries
media
multiupload_filefield_widget
multiupload_imagefield_widget
views
votingapi

Create a content type with the following fields:

Label        	Machine name   	Field type        	Widget
-------------------------------------------------------------------------
Title         	title                  	Node module element
Fivestar    	fivestar            	Fivestar Rating 	As stars
Image      	field_image	  	Image                	Image
Company     	field_company	Text                    	Text field
Price $     	field_price       	Decimal             	Text field
Guarantee	field_guarantee	Text                    	Text field
Body        	body                	Long text and summary	Text area with a summary

Add 2 nodes of this type.
Edit and set their 5-star rating.
Delete fivestar field ---> (Error happens)
Try to disable the module.

After that the ENABLED checkbox for Fivestar in admin/modules becomes non-changeable (greyed and permanently selected) and DESCRIPTION says "Required by: Drupal (Fields pending deletion)"