We’re at practically the same point in the build. I had a similar problem when my epoxy thickened too much to saturate the fiberglass tape. My garage is much warmer than yours at peak temperature, though I was working in the evening when the temperature was closer to 80 than 90. The epoxy eventually thickens regardless of the ambient temperature, and I simply waited too long before abandoning the thickened epoxy for a new batch, or I mixed too much. I mixed less than the 8 ozs. the manual suggested, but I presumably also worked more slowly than the manual anticipated.

Three of my joins look good, but one looks at least as glassy as yours, and I have a patch of unsaturated tape about the size of my thumb. I agree with Bob that your join only needs standing, and any cosmetic issue is negligible, since you’ll presumably cover it with foam or other insulation.

I don’t think the extra epoxy increases the chance of a crack. One of my top panels had an apparently flawless join. The other looked more like yours even after sanding. The one with the flawless join cracked when I tried to place it in the mold. Pictures are in the “Omitting the galley” thread. The crack was not near the puzzle joint, so I don’t think the strength of the join had anything to do with it. I’m still waiting for feedback from CRC on how to proceed.