non-green view shows purple status 🔗 link

All non-green view shows purple status for one of my custom column. But
when I click on it, then it shows green and I see the date & time is
updated on browser which mean that the data is receiving on time at xymon
end.

I need to drop that column and then it comes back to green again. Where
should I look to avoid drop always which deletes the history also.