Forwarding a "Test Email" to coworkers

Hey all -
Looking to get some insight. I work in a marketing department with 8 people. Normally when I send a test email to myself I will forward it onto my department to review and check the links, space, spelling, etc, within the email. Well we noticed that when the test email was forwarded the whole format of the email would get messed up and so I would have to go back into the campaign design and fix the formatting.

The other day I sent a campaign to 5 people in my department and they were seeing the email with no issues with the formatting, but once it was forwarding onto others, it was messed up.

Has anyone else experienced this? Secondly, if the contact who receives the campaign decides to forward the campaign onto their boss, would the email formatting get messed up like it does when we test it?

Hey! Can you screenshot was was messed up? Did the font change? The formatting? Columns, etc.