I did find this paper where somebody used the term “mindless reading”
Smallwood, J. (2011). Mind‐wandering while reading: attentional decoupling, mindless reading and the cascade model of inattention. Language and Linguistics Compass, 5(2), 63–77. https://doi.org/10.1111/j.1749-818x.2010.00263.x
Seems that is the term used for it such as this talk in 2006
Abstract: "Mindless reading" occurs when, during reading, our eyes continue to move across the printed page in spite of the fact that we are busy thinking about things that are often completely unrelated to the text.
I can sometimes do this without my attention even shifting. I'll mentally read every word individually for a while, but forget to put them together to actually understand them.