The only bug I found on the internet related to this issue is the following:
https://github.com/elastic/kibana/issues/1561
Try going to 'Configure Dashboard' (gear icon in upper right), navigate to the 'Index' tab, and press 'Save'. Is there any difference? What if you modify the index pattern very slightly and then change it back?
For instance:
Change Index Pattern *from* logstash-YYYY.MM.DD *to* stash-YYYY.MM.DD - press save.
Change it back and press 'Save'.
I have asked the developers about the screenshot you sent in - I'm waiting on that response.
Is there any impact in functionality, or is this a visual bug?