Why are fillable PDFs running slowly now?

Hello all,

I have been using and updating various forms of the same fillable PDF for over a few years now. It has numerous fillable forms that, in the past, I could quickly cycle through using tab and fill in with ease. However, in the last few days these PDFs have begun to be sluggish and lag when simply scrolling from 1 page to the next. I have disabled some of the enhanced security features as recommended in similar looking posts, this has not seemed to make much of a difference. If anyone has a fix or recommendation, please let me know. 

Thank you