Error not obvious on form when using Tabs

I can reproduce this issue when working with horizontal tabs. Seems like this issue was closed when it was fixed for the accordion field group.

I think this is only happening when a custom error is set using setError() as follows.

$form_state->setError($form['field_name']['widget'][0]['value'], 'Please enter name.');

Please update the issue summary accordingyly. Fixes should go into 4.x. Also needs tests.