I cannot add tabs to certain shapes in WAM

Hi, Does anyone ever have a situation where WAM won’t let you add tabs to certain shapes? Not manually or automatically. If I upload 3 different files I am, for example, able to add and modify tabs on two of the shapes/files but not the third. SO…I redid the file (a simple 2" triangle) and uploaded it by itself. Still no tabs possible.

Thanks in advance,