Consider this wikitext
{|
|{{Grade II colour}}|X
|style="color:<nowiki>red</nowiki>"|Y
|style="color:<nowiki>
green</nowiki>"|Z
|}
<div {{Grade II colour}}>A</div>
<div style="color:<nowiki>red</nowiki>">B</div>
<div style="color:<nowiki>
green</nowiki>">C</div>In all except the first table cell, the style attributes are properly handled. This is likely an edge case difference in attribute parsing in TableFixups DOM handler
The <nowiki> in the style attribute was perhaps an attempt to workaround T5158: Parser inserts invalid in the middle of style attribute (French spaces)/T197902: Be more selective in applying French Space armoring, which was fixed in July 2018?
Current parsoid output for the test case wikitext above:
$ echo -n | bin/parse.js --pageName User:cscott/T222266 <!DOCTYPE html> <html prefix="dc: http://purl.org/dc/terms/ mw: http://mediawiki.org/rdf/" about="http://en.wikipedia.org/wiki/Special:Redirect/revision/895030248"><head prefix="mwr: http://en.wikipedia.org/wiki/Special:Redirect/"><meta charset="utf-8"/><meta property="mw:pageNamespace" content="2"/><meta property="mw:pageId" content="60633826"/><link rel="dc:replaces" resource="mwr:revision/0"/><meta property="dc:modified" content="2019-05-01T15:20:40.000Z"/><meta property="mw:revisionSHA1" content="68d05a01c3a5c6743d96a854d9754428a3b4fcc1"/><meta property="mw:html:version" content="2.1.0"/><link rel="dc:isVersionOf" href="//en.wikipedia.org/wiki/User%3Acscott/T222266"/><title>User:Cscott/T222266</title><base href="//en.wikipedia.org/wiki/"/><link rel="stylesheet" href="//en.wikipedia.org/w/load.php?modules=mediawiki.legacy.commonPrint%2Cshared%7Cmediawiki.skinning.content.parsoid%7Cmediawiki.skinning.interface%7Cskins.vector.styles%7Csite.styles%7Cext.cite.style%7Cext.cite.styles%7Cmediawiki.page.gallery.styles&only=styles&skin=vector"/><!--[if lt IE 9]><script src="//en.wikipedia.org/w/load.php?modules=html5shiv&only=scripts&skin=vector&sync=1"></script><script>html5.addElements('figure-inline');</script><![endif]--><meta http-equiv="content-language" content="en"/><meta http-equiv="vary" content="Accept"/></head><body data-parsoid='{"dsr":[0,240,0,0]}' lang="en" class="mw-content-ltr sitedir-ltr ltr mw-body-content parsoid-body mediawiki mw-parser-output" dir="ltr"><table data-parsoid='{"dsr":[0,107,2,2]}'> <tbody data-parsoid='{"dsr":[3,105,0,0]}'><tr data-parsoid='{"autoInsertedStart":true,"dsr":[3,104,0,0]}'><td about="#mwt18" typeof="mw:ExpandedAttrs" data-parsoid='{"a":{"{{Grade II colour}}":null},"sa":{"{{Grade II colour}}":""},"dsr":[3,25,21,0]}' data-mw='{"attribs":[[{"txt":"style=\"background-color: \"","html":"<span about=\"#mwt1\" typeof=\"mw:Transclusion\" data-parsoid='{\"pi\":[[]],\"dsr\":[4,23,null,null]}' data-mw='{\"parts\":[{\"template\":{\"target\":{\"wt\":\"Grade II colour\",\"href\":\"./Template:Grade_II_colour\"},\"params\":{},\"i\":0}}]}'>style=\"background-color: </span><span typeof=\"mw:Nowiki\" about=\"#mwt1\" data-parsoid=\"{}\">\n#ACE1AF</span><span about=\"#mwt1\" data-parsoid=\"{}\">\"</span>"},{"html":""}]]}'>X</td> <td style="color:red" about="#mwt4" typeof="mw:ExpandedAttrs" data-parsoid='{"a":{"style":"color:red"},"sa":{"style":"color:<nowiki>red</nowiki>"},"dsr":[26,63,36,0]}' data-mw='{"attribs":[[{"txt":"style"},{"html":"color:<span typeof=\"mw:Nowiki\" data-parsoid='{\"dsr\":[40,60,8,9]}'>red</span>"}]]}'>Y</td> <td style="color: green" about="#mwt7" typeof="mw:ExpandedAttrs" data-parsoid='{"a":{"style":"color:\ngreen"},"sa":{"style":"color:<nowiki>\ngreen</nowiki>"},"dsr":[64,104,39,0]}' data-mw='{"attribs":[[{"txt":"style"},{"html":"color:<span typeof=\"mw:Nowiki\" data-parsoid='{\"dsr\":[78,101,8,9]}'>\ngreen</span>"}]]}'>Z</td></tr> </tbody></table> <div style="background-color: #ACE1AF" about="#mwt20" typeof="mw:ExpandedAttrs" data-parsoid='{"stx":"html","dsr":[109,141,25,6]}' data-mw='{"attribs":[[{"txt":"style","html":"<span about=\"#mwt8\" typeof=\"mw:Transclusion\" data-parsoid='{\"pi\":[[]],\"dsr\":[114,133,null,null]}' data-mw='{\"parts\":[{\"template\":{\"target\":{\"wt\":\"Grade II colour\",\"href\":\"./Template:Grade_II_colour\"},\"params\":{},\"i\":0}}]}'>style=\"background-color: </span><span typeof=\"mw:Nowiki\" about=\"#mwt8\" data-parsoid=\"{}\">\n#ACE1AF</span><span about=\"#mwt8\" data-parsoid=\"{}\">\"</span>"},{"html":""}]]}'>A</div> <div style="color:red" about="#mwt11" typeof="mw:ExpandedAttrs" data-parsoid='{"stx":"html","a":{"style":"color:red"},"sa":{"style":"color:<nowiki>red</nowiki>"},"dsr":[142,189,40,6]}' data-mw='{"attribs":[[{"txt":"style"},{"html":"color:<span typeof=\"mw:Nowiki\" data-parsoid='{\"dsr\":[160,180,8,9]}'>red</span>"}]]}'>B</div> <div style="color: green" about="#mwt14" typeof="mw:ExpandedAttrs" data-parsoid='{"stx":"html","a":{"style":"color:\ngreen"},"sa":{"style":"color:<nowiki>\ngreen</nowiki>"},"dsr":[190,240,43,6]}' data-mw='{"attribs":[[{"txt":"style"},{"html":"color:<span typeof=\"mw:Nowiki\" data-parsoid='{\"dsr\":[208,231,8,9]}'>\ngreen</span>"}]]}'>C</div></body></html>
Dumping the calls to Sanitizer.normalizeCSS in Parsoid:
NORMALIZE CSS: { text: 'color:red' }
NORMALIZE CSS: { text: 'color:\ngreen' }
NORMALIZE CSS: { text: 'background-color: \n#ACE1AF' }
NORMALIZE CSS: { text: 'color:red' }
NORMALIZE CSS: { text: 'color:\ngreen' }So the first background-color attribute isn't even making it to Parsoid these days, reaffirming @ssastry's theory about this being an issue in TableFixups. (Presumably at one point in the past it made it to normalizeCss since 898c9b9ec1443cd6510313e20059e1ec26f04e09 apparently made the background color appear. We've regressed at some point in the six (!) years since then. Confirmed that Ide0d1b6f503f17124aa9546dcb857adf1938a453 has no effect one way or the other.