Adobe Animate CC 2021 v21.0.7.42652 Auto Lip Sync Problem

@defaultzuy8v7z4k50x where exactly you are seeing the only one symbol ?  Inside frame picker panel or inside Lip Sync Dialog ? If Inside graphic symbol then please check no of frames inside the graphic symbol.

It could be possible that you are having only 1 frame inside the graphic symbol that is why it is showing only 1 symbol, Also check whether it is a nested symbol (suppose you have head symbol and inside that you have mouth_poses symbol, mouth poses has 5 frames and head symbol has 1 frame , then in this case on selecting head symbol only 1 frame will be visible in the frame picker panel and if you go inside the head symbol and select the mouth poses symbol all the frames of mouth_poses symbol will be visible in the frame picker panel.

And if you are facing problem in lip sync dialoge then can you please confirm whether you seeing one mouth expression for all the expressions as shown in the attached screenshot ? If yes then please check by clicking on that symbol whether visme popup is opening to set the different - different mouse poses or not  as shown in the attached screenshot.