Object Mask goes offline in Media Encoder

I generally use Media Encoder to export my media but when I do, I'm getting a warning in ME that the object mask is offline and is not included in the encoding. However, when I use the Export button in Premiere to encode, the object mask is included and encoded. I'm in the latest versions of Premiere Pro Beta and ME Beta. I thought I might have needed to upgrade to Creative Cloud Pro from Standard, so I did that but ME still didn't encode the object mask. The Mask folder is right next to the project file. I'm not sure what's happening or what's missing in my process to Export Media to ME that is causing the mask to go offline. Frustrated.