Swap directory changes when opening files under /media [Fedora]

I'm on Fedora 25. When I open files from mounted filesystems on /media vim runs this (from vim log):

Executing BufReadPre Auto commands for "/media/*"
autocommand set directory=~/tmp,/var/tmp,/tmp

This changes my swap directory from what I want it to be and means I have swap files in two locations. How can I find out why this is happening? I set directory once in my profile:

set directory=~/.vim/swap//

Thanks

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