Recently, a couple of my reps came to me asking if something was wrong with Sales Insight. They suddenly have a bunch of contacts to whom they've sent sales emails, and haven't seen a single open or click. What's weird is it seems to be working if they send via the Outlook plugin, but not if they send directly from Sales Insight in SFDC.
When I investigated, I actually found dozens of contacts who have an "Open Sales Email" activity in their log, but the "open" box in Sales Insight is not checked for them. Has anyone noticed anything like this recently?