Earlier quoted context omitted.
I think this stuff is actually pretty typical for folks who progress to a certain stage. I experienced it as well, if that makes you feel any better. The Buddhists definitely know about this, but a lot of their writing is pretty impenetrable and interlaced with weird metaphysics. Here's some modern, secular words on the subject (from the admittedly controversial author Daniel Ingram): https://www.mctb.org/mctb2/table…
Yeah, it came as a real shock to me at first. I had made many mistakes in my early meditation career. But I learned a lot more and suddenly started progressing. This was wonderful at first. I started to feel and experience some pretty mind-blowing things on the cushion at first and then extending well off the cushion into the rest of my life. Then... I remember random memories started to kind of pop into my awareness…
Also, I'm not very fond of taking the traditional advice so literally. These sources focus solely on training new Buddhist monks, and most people doing secular practice just want some peace of mind while they continue their, productivity focused, western lifestyle.
We need to take these sources with a grain of salt and reorient our practice so that it cultivates more peace of mind without making us implode when the cultivated buddhist mindset creates a conflict with our western lifestyle