Mailhog not working when transactional email service enabled

Local v2.4.3

1-min video demonstrating the issue: https://cl.ly/7d48e925a7bc

The issue is that if I have a transactional email service - such as Mandrill, Postmark, etc - then Mailhog doesn’t record it. However, https://wordpress.org/plugins/email-log/ does show record of the emails sent by the transactional email service.