I had same issue.
A get_current_screen() call is being performed inside the custom namespace MBTM. This it should not do.
I resolved it temporarily by editing the /wp-content/plugins/mb-term-meta/src/MetaBox.php file and adding a php include for the screen.php file. Not necessarily an ideal fix but works til MetaBox fixes the issue and updates.
so @ line 73 in /wp-content/plugins/mb-term-meta/src/MetaBox.php
public function is_edit_screen( $screen = null ) {
require_once( ABSPATH . 'wp-admin/includes/screen.php' ); //<-add this
$screen = get_current_screen();
