For anyone needing a solution in the future, I was able to solve this problem by forcing hardware acceleration. Added this to my .blur css:
-webkit-transform: translate3d(0,0,0);
-moz-transform: translate3d(0,0,0);
-ms-transform: translate3d(0,0,0);
-o-transform: translate3d(0,0,0);
transform: translate3d(0,0,0);