A question about Vanda roots

[NDW76]

Hello everybody. I hope this is the correct place to post this question. If it is not, please feel free to move it the correct place.

I have noticed that the last ten centimeters of the aerial roots on my Vanda orchids are yellow. Above this they look healthy to me, white with a green tip. While all the roots change colour to green when they have had a good spray of water, these yellow parts stay yellow.

I have also noticed that there are a number of dead roots in amongst the live healthy roots. Should these be cut out or are they perfectly safe to leave in place?

And one last question. I have a small shoot growing from the base of one of my Vandas. I'm not worried about this, but is this a normal growth habit?