Multisite wp-admin redirecting incorrectly

I have a multisite set-up for several urls, subdomain set-up. I have the domain mapping plugin installed. I can get to the root website wp-admin url no problem, but when I try to get to one of the child sites, it tries to redirect me:

https://devuniversity.utest.com/https%3A%2F%2Fdevuniversity.utest.com%2Fwp-admin%2F

It should be: https://devuniversity.utest.com/wp-admin

Typing in the correct url also causes the bad redirect.

I’m using the suggested .htaccess:

RewriteEngine On
RewriteBase /
RewriteRule ^index\.php$ - [L]

# add a trailing slash to /wp-admin
RewriteRule ^wp-admin$ wp-admin/ [R=301,L]

RewriteCond %{REQUEST_FILENAME} -f [OR]
RewriteCond %{REQUEST_FILENAME} -d
RewriteRule ^ - [L]
RewriteRule ^(wp-(content|admin|includes).*) $1 [L]
RewriteRule ^(.*\.php)$ $1 [L]
RewriteRule . index.php [L]

And I’m using vhost entries for all of the subdomains.

All of the pages load as normal, I just can’t get to the wp-admin of any of the subsites.