ToDos image not found issue

There is an pending issue: Next warning is thrown on the log:

7:44:18,570 WARN [http-bio-8080-exec-29][code_jsp:128] {code="404", msg="/html/js/aui/calendarnavigator/assets/skins/sam/data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAABgAAAAOCAYAAAA1+Nx+AAAAGXRFWHRTb2Z0d2FyZQBBZG9iZSBJbWFnZVJlYWR5ccllPAAAAQhJREFUeNqs0yGLAlEUhuHrKoIgCFbBJghb3F+g0WrVarEqLIhBEEFYWKNNMBktU4z6C5RNkwyCyWQSTPuOfCOCrHNnxwMPyOGe73DAiTmOYywrhy/9/sTBZujN4k0KPbioi6teKuqCmsKGSN/10+q5ehN6QQkrLJB/Mp/Xm5VmAhdkMcEGZWNfZc1MlPGwII42dmiZ/1dLGW1lXhdU8YNvZEz0yijLy6z6FyTN6yvpX7DEOzo4vSD4pCwvc+lfcMEYBUwjhE+VMVbmw7/oiCY+sA4RvNZMUxmB38EWFTSwfxK815uKZkJ/yXMU0cf5rn9Wr6g3f1bC4nwvbIAZRup1Ay671a8AAwC3OzOqxK+rkwAAAABJRU5ErkJggg==", uri=/html/js/aui/calendarnavigator/assets/skins/sam/data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAABgAAAAOCAYAAAA1+Nx+AAAAGXRFWHRTb2Z0d2FyZQBBZG9iZSBJbWFnZVJlYWR5ccllPAAAAQhJREFUeNqs0yGLAlEUhuHrKoIgCFbBJghb3F+g0WrVarEqLIhBEEFYWKNNMBktU4z6C5RNkwyCyWQSTPuOfCOCrHNnxwMPyOGe73DAiTmOYywrhy/9/sTBZujN4k0KPbioi6teKuqCmsKGSN/10+q5ehN6QQkrLJB/Mp/Xm5VmAhdkMcEGZWNfZc1MlPGwII42dmiZ/1dLGW1lXhdU8YNvZEz0yijLy6z6FyTN6yvpX7DEOzo4vSD4pCwvc+lfcMEYBUwjhE+VMVbmw7/oiCY+sA4RvNZMUxmB38EWFTSwfxK815uKZkJ/yXMU0cf5rn9Wr6g3f1bC4nwvbIAZRup1Ay671a8AAwC3OzOqxK+rkwAAAABJRU5ErkJggg==}

It seems it is because the liferay minifier, because the related css has an image conent encode in base 64 in the css itself. Probably when the minifier tries to minimize the css file spoil the image.