Good news! I redownloaded that episode and the new copy seems perfect. No glitch.

I think the capture the wight ark could be used if it was simply changed to Jon wanting to give Dany proof, while not bothering with proving it to Cersei. As it stands now, the planning part makes no sense because you don’t know what they’re even planning until the end of the conversation. I think the change makes the ark worse and unclear to the viewer. Same with Brenjen. Sometimes you just need to accept that something can’t be fixed and leave it as is.