In section 7.2.3 of Grid we specify that resolving 'fr' units with summed value of less than 1, during intrinsic sizing, should match Flexbox. Looking at the current implementations in Chrome and Firefox the behavior doesn't seem to match that expectation.

Consider this test case. The expectation is that when the sum of all fractions is less than one we have the special case. The implementations behavior is inconsistent and it appears to be triggered when at least one 'fr' value is less than 1.

If these are implementation bugs I can follow up with filing them but I'd like to make sure the spec is clear and if not we should be more explicit.

Here's a reference of the correct behavior in flexbox here.