Is it normal for a post's rankings to heavily fluctuate?
lI had this one post where it was doing well at position 12 for months. Then a few days ago I made some editing (putting an affiliate linked image on the top of the page before any written content) and the next day the rankings disappeared and it's "NOT FOUND".
So in panic mode I changed it back to the way it was, and the next day I sighed of relieve because I got the rankings back. Now I checked again and it's almost gone again. Take a look at the picture illustrating the ups and downs:
Other posts has been happening like this. one day it's position 32, next day it's "NOT FOUND" This particular post I have not even edited in any way since it was published:
I googled some of the possible things that can cause this, but I'm unable to figure out for sure which one it is.
should I be worried about this? is this normal?