I have started testing the Editorial theme version 2.3.8, and the first problem I have encountered with 1.8.0-beta.7 is in the metadata.html.twig file (line 36). Here's the error:
The "filter" filter expects a sequence/mapping or "Traversable", got "null" in "partials/page-bits/metadata.html.twig" at line 36
This is line 36:
{% for item in theme_config.social if item.name|lower == 'twitter' %}
If I change it to:
{% for item in theme_config.social|default([]) if item.name|lower == 'twitter' %}
or wrap it in an if condition:
{% if theme_config.social is defined and theme_config.social is not null %}
it works correctly.
I don't know if this is a problem in Grav 1.8, or if in this version, validations for null values are stricter. In Grav 1.7 if theme_config.social is null, it works.