Error when running from a non-accessible directory (afuse mount as user, vim as root)

[blueyed]

I have just noticed the following error when starting Vim from a directory mounted using afuse:
1. afuse -o mount_template="sshfs %r:/ %m" -o unmount_template="fusermount -u -z %m" ~/sshfs/
2. cd ~/sshfs/example.com
3. sudo vi /etc/fstab

Error detected while processing function QuickfixsignsSet..<SNR>83_GetList..quickfixsigns#vcsdiff#GetList:
line   22:
E344: Can't find directory "/home/user/sshfs/hahler.de" in cdpath
E472: Command failed
Error detected while processing function QuickfixsignsSet:
line   45:
E171: Missing :endif

The problem appears to be that the mount point is only accessible by the user itself, and not by root.