🇬🇧United Kingdom @jkdaza

Patch #48 works for me, but

list($target_type, $revision_type) = explode(':', $target_type_and_rev);

assumes that the $target_type_and_rev will always have 2 values. This is not the case, so you end up with tons of warnings>
I've changed it to

list($target_type, $revision_type) = array_pad(explode(':', $target_type_and_rev), 2, NULL);

and no more warnings.

Attaching the revised patch.

#17 🐛 Passing null to mb_strlen is deprecated in template_preprocess_username Postponed: needs info really helped, thanks!

We also experienced this issue and we tracked it down to one of the custom modules implementing `hook_user_format_name_alter` was returning NULL for anonymous users.

I changed this:

function MYMODULE_user_format_name_alter(&$name, AccountInterface $account) {
  $name = $account->getEmail();
}

into this:

function MYMODULE_user_format_name_alter(&$name, AccountInterface $account) {
  if ($account->isAnonymous()) {
    return;
  }
  $name = $account->getEmail();
}

jkdaza → created an issue.

I have experienced the same issue on a couple of sites after upgrading from 9.5.x to 10.1.x.
I can replicate the issue on Chrome and Firefox, using both Mac OS and Windows.

The patch in #23 fixes the layout issue.