CustomerUserListFields => Friendly mail name?

[GHoeffner]

Hello OTRS community,

when we change the "CustomerUserListFields" setting to this value:

CustomerUserListFields => ['login', 'first_name', 'last_name', 'customer_id', 'email'],

the E-Mail "To"-header is modified to that value as well... why is it doing that? Shouldn't it be for displaying only?
Does anyone know how to stop this behavior?

Thanks in advance.