Beyond this sign, are you obliged to give way to vehicles approaching from the right at the junction?

Why?

The D-48 sign shown contains the A-5 symbol, warning of a change to equal-priority rules at the next junction. You must therefore be prepared to give way to a vehicle approaching from your right.

§ 59 rozporządzenia w sprawie znaków i sygnałów drogowych; art. 25 ust. 1 Prawa o ruchu drogowym