Public Folder permissions you set in Outlook/Exchange are not propagating to the items within the folder.
Microsoft strongly recommend that you do NOT alter permissions via the M drive. However I cannot see any way around this issue.
I have tried the following article to default the permissions:
Although this works quite happily at folder level it does not seem to propogate to the items
Is there a way to reset the permissions on the public folder items to inherit their permissions from the public folder?