FEED error (_lastBuildDate)

This may be a plugin or theme conflict. Please attempt to disable all plugins, and use one of the default (Twenty*) themes. If the problem goes away, enable them one by one to identify the source of your troubles.

Sorry for my slopiness, i forget to to mention that it was the first thing i’ve done. But with all plugins deactivated and wordpress with custom theme it still receiving error messages in feed validator.

What version (en, br, etc.) did you install? I’m looking for a pattern among the folks who’ve reported similar problems.

OK, turns out it’s a bug that will be addressed in WP 4.7.1.

See https://core.trac.www.ads-software.com/ticket/39141

Oh yes! It’s really a version core trouble, i’ve solved the first problem (date) with the code above in functions.php:

<?php
add_filter(‘date_i18n’,’rssfeeds_date_donttranslate’,10,4);
function rssfeeds_date_donttranslate($j, $req_format, $i, $gmt){
if(is_feed())
return date($req_format);
else
return $j;
}

And the “XML parsing error” was solved

But unfortunately now i’m getting other error messages, cleary is something with the 2 last posts, i try copy the post content, create a new post with the same text but i keep receiving error:

line 38, column 488: XML parsing error: <unknown>:38:488: not well-formed (invalid token)

Well, by the way this problem of “not well-formed” feed is unsolvable.