It is confusing that the "Email Suspended" field does not ever switch back to false after it is triggered. While I do understand the functionality and reasons for this field not switching back, it is still confusing for new customers to Marketo.
Since this is a historic field that does not reset, I suggest to change the name of this field to "Email was Suspended" to indicate that it is a historic field. When people look at this field title, they will know that it may not be a current value and will be encouraged to look at the "Email Suspended At" field to see if the lead is still suspended.