I’d never noticed these until my latest viewing. The senior officers have ‘parade caps’ which they almost never wear. Here we can see Dr. Petrov wearing his during the evacuation after the ‘reactor accident:’
And here are Borodin and Ramius with theirs, which appear identical with the exception of additional gold wreaths on the bill:
Note that these appear to be using the same badge as the ushankas, and the buttons holding the braid appear to be the same as the smaller Soviet naval buttons.