In Game of Thrones, S08E03, The Long Night, [~18minutes into the episode] Arya gives her Valyrian dagger to her sister, Sansa, as she tells her to go down to the crypt. Confirmed [~47minutes in] when Arya uses Dragonglass, instead of the dagger, to kill the wight in the library. Only to have the dagger back in her hand(s) [~78minutes in] when she kills the Knight King. All with apparently no interactions in the crypts to regain the dagger from Sansa. Can anyone offer a reasonable explanation?
Some fans thought that Arya gave the dagger to Sansa at the beginning of the episode. After the wights proved unstoppable, Arya told Sansa to go down to the crypts and to take the dagger to protect herself. We only see the hilt and can assume it’s the Valyrian steel dagger. But Sansa flashes the dagger to Tyrion in the crypts as they hide from the Wights and we see that it is dragonglass.
Arya didn't give Sansa the catspaw dagger.
The dagger that Arya gave Sansa was just an "ordinary" dragonglass dagger.