I suspect it is prepositioned gear replacement for Germany.
Much of what was prepositioned is in Poland now or on its way, a “heavy” brigade set I think. Prepositioned stocks in Germany have been “raided” for years for various needs, plus obsolete stuff has been sold or returned to the US for upgrade or storage.
Polish T-72s are now being fitted with reactive armor, but they lack modern sights. When they will be ready to enter Ukraine is not presently known