Hello Nina,
We've had some confusion about the way both the Members Manual and Owners Manual describe the Max Attachment Size setting for subscriptions. Based on our testing, it would appear that if the total size of attachments is over the preferred setting, then all attachments are sent as links. The confusion came about because some thought that smaller attachments would be sent and only larger ones would be linked (in the same message). You might want to verify this with Mark in case it's actually a bug.
Thanks,
Duane