"this field is present in your elasticsearch mapping" on _source field

Upgraded my ELK stack to 6.8 finally. Beats are on 6.4 still. Zero issues all last week and all this week. Today I noticed one of my filters for one of my beats was experiencing some parsing errors on certain log entries. Made an updated filter, tested, parsing correctly and everything is working.

Get call for details on some logins. Start going through logs using Kibana. Everything is working fantastic. I change to the next timeframe and suddenly one of my Kibana columns is now showing _source right next to Time. To make things worse it seems to me the data for entire log record AND I cannot remove it as as column.

I then notice it is listed to the left under the Selected Fields and has a "?" next to it. Expanding this gives me the "This field is present in your Elasticsearch mapping but not in the 94 documents shown in the doc table. You may still be able to visualize or search on it."

No idea why this suddenly showed up. I was literally searching my indices one moment then like I said all I did was change timeframe and it was there. Everything seems to still be technically working, however I want to remove this column, and my greater concern is why I am getting this error on what I thought was a default meta field all of sudden?

Any advice would be greatly appreciated as I am starting to use this system more and more.

Just bumping this so it is not closed. Surely I am not the first to encounter this problem.

You can try refreshing the index pattern in Kibana.