iOS 10.3: NSStrikethroughStyleAttributeName is not rendered if applied to a sub range of NSMutableAttributedString

Setting the baseline offset seems to fix it:

[attributedStr addAttribute:NSBaselineOffsetAttributeName value:@0 range:NSMakeRange(0, 10)];
[attributedStr addAttribute:NSStrikethroughStyleAttributeName value:@2 range:NSMakeRange(0, 10)];

This is a known bug in iOS 10.3