Email app glitching with pdf attachments?

Whenever I open the mail app on my iphone 8+ it randomly flashes the last pdf file I opened on the screen before going to mail. Even if it's already been deleted. Is this normal? Seems like a glitch, but I haven't seen this question asked anywhere else.

Also, the pdf's that are flashing on the screen are all from an Office 365 Exchange account, if that matters.

Thanks,