Thanks trurl,
Looks like you've directed me in the right direction and it appears my appdata is set to shareUseCache="prefer"
From diag:
appdata shareUseCache="prefer" # Share exists on cache, disk1, disk2
d--a shareUseCache="yes" # Share exists on cache, disk1, disk2
domains shareUseCache="prefer" # Share exists on cache
isos shareUseCache="yes" # Share exists on disk1
system shareUseCache="prefer" # Share exists on cache
Does that look correct?