If you have a site using the AMP plugin in “Reader” (formerly “Classic”) mode – which is to say it uses some simple templates for rendering AMP pages – you should remove Glue for Yoast SEO & AMP:
– it is no longer necessary
– the code in glue-for-yoast-seo-amp/classes/frontend.php adds a duplicate inline CSS selector for
header.amp-wp-header
and
.amp-site-title a
. This means the default colour scheme will override colours you set in Appearance > AMP.
Disabling the plugin fixes this.
(Tested with AMP 1.5.5, WordPress 5.4.2)