New masking tool effect dosen't show when exportd on Media Encoder beta

[ESSTLL3]

Hello, I tried the new "object mask tool" in Pr Beta (works so great!!) Everything was fine when I exported my video from Pr directly. But when I exported the same video in Media Encoder (beta), the Mask I used in the project did not applied. 

System info :
    Application: Adobe Media Encoder (Beta) v26.0.0.36
    OS: macOS v15.7.2, RAM: 32.00 Go GB, CPUs (logical): 10