I too have been having issues with global email filters for the past 2 weeks. It seems there was possibly an update to CPanel with my host provider about that time that broke a couple of the actions within the filter page.
If I try to forward any emails using the action "Redirect to Email" you get this error:
[removed - please upload attachments directly to the thread]
It only works if you forward to an address that's NOT part of your domain (ie., a gmail or yahoo account works). To me, I think someone got a bit overzealous when updating the rules for actions so there wouldn't be any issue with recursive errors, understandable, but a bit too tight on the allowances of what we can do with the filter process.
To further exacerbate the issue, the "Deliver to a Folder" action doesn't work either. I've tried using every available folder within the drop down menu when I select that action, but no mail ever gets delivered to the folder.
I've contacted my provider to address this issue, but most of the replies are to "just use spam assassin, it works much better", which translates, at least to me, "I don't have time to work with CPanel to fix this issue".
Right now, I still have a few older filters set up with the "Redirect to Email" action, but I don't believe its actually working any more, as I'm not seeing any mail forwarded to my spambox email. I know if I try to edit and save any update to the older filters, I'll end up with that same error in pink above and I am not able to save the filter after that unless I remove either of the two actions I've mentioned.
Sure hope to get a response from the CPanel folks about how to go about fixing this issue! It would be great to have control over the spammy emails I'm getting again!!!
Oh yeah, the CPanel version I'm referring to is 76.0 (build 18).