In this situation, does the yellow flashing signal permit entry beyond the signalling device?

In the video you are approaching a junction in town; traffic lights above the roadway show a flashing amber signal, next to them there is sign A-7 "give way", and on the left there is B-2. The flashing amber signal permits entry beyond the traffic lights. The answer is: yes.

The Regulation on road signs and signals states that a flashing amber signal shown by traffic lights warns of a danger or an obstruction to traffic and requires you to exercise particular caution. It is not a ban on entry - unlike a red signal or a steady amber signal - so you may continue, but the junction then works as if there were no traffic lights: right of way is decided by the signs. Here there is A-7, so you must give way to vehicles travelling on the intersecting road and, if necessary, stop. Flashing amber is switched on at night, when the traffic lights fail, or at junctions where the traffic lights are only a warning; many drivers then instinctively look for "their" green and drive in without looking at the signs, which ends in collisions. You slow down, look both ways, give way to whoever you must and drive through when the road is clear.

Legal basis: § 98 para. 6 and § 5 para. 5 of the Regulation on road signs and signals; Art. 5 para. 1 of the Road Traffic Act (Prawo o ruchu drogowym)