This is still totally valid. I'm playing with 1.4 to go for the SISAS, and this has been bugging me. I downloaded the HydrantID SSL ICA G2 root cert, and that fixed it for me as well!
Thanks!
I have 2 5506-X both on 9.5(2) with the same issue, not in HA. I have 2 more I'm building for clients today as well. I'm guessing I'm going to see the same problem...