Did you file a bug report from your previous thread?
https://forums.macrumors.com/threads/1130377/
I noticed my Spotlight was going crazy the other day. I had to stop the process, sudo mdutil -a -i off
then delete the index,
sudo mdutil -E,
then re-index,
sudo mdutil -a -i on
and it has worked fine since then. This was from normal usage not after using Reeder.