wheres the masking option gone?

With new Masking, the buttons have been removed from the ECP and are now in the Tools panel along with updated functionality. You can find more information at https://community.adobe.com/t5/premiere-pro-beta-discussions/now-in-premiere-pro-beta-new-masking-tools/td-p/15484479

Its not a bug: they have been removed from the program.

You now have to use the new mask feature.