Thievery Alert: Programs Stealing Acq. Credit

Lately we've discovered that we have programs stealing acquisition credit from other programs. For example, someone first comes in to our database through a list purchase and then at some point later in time registers for a webinar, the webinar will change the acquisition program and channel.

I adjusted the smart list in our Acquisition smart campaigns to include the filter Acquisition Channel is empty. However, this morning I see that someone who had an acq. channel as List Purchase made it through the Acquisition campaign of a webinar program and had it changed. Here's a couple screenshots below:

The person was created in 2017 so the issue is not with the 20 minute window. Appreciate the help!