Sous Vide and frozen meat

I typically buy large vacu-sealed boneless Rib Roasts (Choice) from Costco and cut them into steaks approximately 5/8 of an inch thick. I then vacuum seal them, 2 to a package using a food saver system. When preparing them, I go directly from the freezer to a 135f water bath (using an Anova circulator) for about 2 hours. I then take them out, season them with salt and pepper and finish them on a hot grill for about 1 minute per side.
The result is quite disappointing. The bag after sous vide cooking has more juices than I would have expected. The meat has reasonably good flavor but is dry and not all that tender.
Can anyone give me an idea as to what I am doing wrong - is it the fact that I am using frozen meat? The same meat cooked on my grill without using sous vide is much better.