Chrome Version: 67.0.3393.4 (Official Build) dev (64-bit)
OS: Linux

What steps will reproduce the problem?
Load this content into a web page and inspect the styles in devtools:

<div style="place-items: start legacy"></div>
<div style="place-items: start left legacy"></div>
<div style="place-items: start legacy left"></div>

What is the expected result?
all the specified values should be accepted as valid values

What happens instead?
none of the specified values are accepted as valid values

Relevant spec:
https://drafts.csswg.org/css-align-3/#place-items-property

place-items was updated relatively recently so that the shorthand now includes all individual values of align/justify-items