Are you talking about the built in JSS method of deploying a dock icon or will a 3rd party tool like dockutil? I had assumed the former, but wasn't sure since dockutil was mentioned above.
Finding a similar thing as well, has just started. We only use the JSS method of deploying Dock icons. We have two policies which add a dock item each. The policy logs say that the policy has run, but the dock items don't appear.
I have been experiencing the same behaviour recently (since upgrading to 8.71). It seems to be affecting some dock icons but not others. Most of the time deleting the icon from Casper Admin and re-importing seems to do the trick but not always. No errors logged anywhere either...
