I have two Brinsea 20 Eco incubators. Both have constantly fluctuating temps. Maybe they had production problems this year? Either way, they have ruined my trust in them. And I even use their EcoGlow brooders. Now I am going to question using those. At least with the EcoGlows, the chicks can run out rather than be baked.I'm sorry you had an issue. I never have, been using for several years.
I am buying a GQF Sportsman cabinet or a few more Rcoms. I have never heard of someone telling me either cooked their eggs in those two brands.