General Tile Discussion

I was finally making headway on my bath remodel project and now hit another issue. I finished tiling and grouting approximately 130 sq ft of bathroom floor. I saw a couple of YouTube videos touting Prism SCG and decided to use it. I had to remove a mirror and move a couple of electrical outlets/switches on a wall to make room for a new vanity that is being delivered tomorrow. I just started cutting wall tiles and noticed a small void in the grout near the shower pan. I used my utility knife to scrape the grout in the area and found it very soft, almost like chalk. I can stick mi knife right into the grout and remove it with little effort. I have done so in approximately 15 sq. ft. It’s been a week since I grouted. I’m beside myself. Has anyone used Prism SCG? Have you had problems? I’m calling CBP tomorrow. Any other suggestions or recommendations?