I assume that this is a 1.8 SP issue, don't know if it will be a non-issue when 1.8 is released officially, and I have submitted a report to the ninjas. Having said that, some (not all) of the 1.8 SP releases wipe out the custom perspective icons on the iPhone when synced for the first time. The custom icons are still displayed on the Mac, but the generic perspective icon is displayed in OmniFocus for iPhone. Any icons that are included in OmniFocus are still retained on the iPhone. To get the custom icons back, I need to re-assign them on the Mac and sync them to the phone again.
On the Mac:
On the iPhone:
