Placeholders problem with rejected mail

Hello,
I have a problem with the placeholders specially : {display_name}
But only with one type of mail : Rejected Account

The placeholder {display_name} ( and {first_name} & {last_name} ) display the name of the admin who rejected the person.

I make few tests to arrive at this conclusion.

In others types of mails that works well so i think it’s a bug from WpMember, but not sure.

Is it normal ?

If not, how do i do to fix it ?

Thanks