Hello,
I've released version 3.8.0.1 of the Foundation theme for Moodle 3.8beta (you'll need build '20191112'): moodle.org/plugins/pluginversion.php?id=20575.
This has the same functionality as version 3.7.1.2 - moodle.org/mod/forum/discuss.php?d=393437 - but made to work with Moodle 3.8.
This is 'beta' code on both accounts so indeed could have 'issues'. Certainly for test servers only!
Please post any issues with this version here ONLY.
If you find this post useful then please mark it so.
Gareth