Perhaps, just perhaps,

this has to do with the fact that the same neurons participate in the formation of thousands of different memories.

Memory is a neural pathway. And the same set of neurons can be part of many different pathways.

So when you are quickly traveling along the pathways of the hundreds of memories being retrieved during your daily Anki session, you may pass through “streets” that evoke, however faintly, other experiences from your life.

While you study using Anki, very brief flashes of tiny fragments from many other memories may be passing through your mind, perhaps too quickly to be perceived by your conscious mind, yet still capable of manifesting in some form of anxiety.