Howdy,
If you are talking about Bohnings "Ferr-L-Tite CoolFlex" I've had the same thing happen in both hot and cold temps. I think it gets gooey when it's hot, and brittle when it's cold.
I've had less trouble when it's hot, I think I had one insert come out, but it doesn't get super hot here for very long.
When it's cold I've had several inserts pull out in foam targets, the foam gets denser and the glue gets brittle.
I still think it's useful, as I was able to pull different weights of inserts in and out when I was testing different spines of arrow and such, but I've come to view it as a temporary adhesive.
I'm using epoxy on my hunting arrows.