I trust you've read the article cited by JeteMc in Post#9.

To go a step further.

Are there any values in $C$6:$CX$1805 that reference directly or indirectly:

  • Cells that have any volatile functions?
  • Dynamic Named Ranges that contain volatile functions?
  • Named formulas that contain volatile functions?

The point being that volatility is also inherited.
That is a point not often raised on the topic.