Can I get confirmation of this

I assume that if something lasts until the end of the phase (such as giving a character a trait) then during the End of Phase stage that that effect is no longer active

e.g. Challenges

I give one of my characters House Tully trait until the end of the phase

Riverrun

At the end of the challenge phase ... each House Tully character ....

FAQ 2.6, End of Phase (p. 9):

“Until the end of the phase” lasting effects

expire in step 3 of the “End of Phase”

framework action window.

“At the end of the phase” passive effects

initiate in step 4 of the “End of Phase”

framework action window.