Warning: lost a full clear coat on a black Silverado last Tuesday because I trusted the gauge on the wall
Last Tuesday I sprayed a black Silverado and the booth gauge on the wall read 72 degrees, so I mixed my clear like normal and went to lunch. Came back and the whole panel looked like an orange peel smoothie, and I burned through 3 hours and about $90 in clear trying to wet sand it back. Turns out the gauge was 8 degrees off from the actual booth temp and my activator was way too slow for the real number. Check your gauge with a handheld at least once a week, mine had been lying to me for who knows how long. What temp variance do you guys see between your wall gauge and your handheld?
A handheld can be off too if it's been dropped or sitting in a hot truck, so chasing the exact number might be the real problem. Sounds more like your activator was just too slow for that job and the gauge gave you an easy thing to blame.