Here is a comment from ZWO https://astronomy-imaging-camera.com/tutorials/what-is-amp-glow.html
“Glows may not “grow” with time the same way dark current itself does, and may accelerate over time becoming brighter faster than dark current itself as exposures become longer.”
Although I could not find my initial source I found this analysis which is similar https://jonrista.com/the-astrophotographers-guide/the-zwo-asi1600-guide/the-zwo-asi1600/preliminary-analysis/
Just to be clear I am not saying the ASI1600MM is not linear. Like Simon Dawes I find mine is very linear but I use darks with the same exposure as the lights and I don’t use bias frames.