I received the following error message when trying to save an email filter on a Cpanel account that had a pipe as one of the filter actions:

Action #1 is invalid: action type “pipe” is unknown

This I was trying to do while logged in as the user of the actual email account.  When I logged into Cpanel for the whole domain I was able to add the email filter there with no problems.  I haven’t seen this error anywhere else on Google so I’m not sure if it’s a widespread bug they have or not but it didn’t work on this system that was up to date.

It should also be noted that per Cpanel documentation the path to the program that the email is being piped to should be relative but I’d get a bounce message unless I used an absolute path.