[ML] Anomaly Explorer - empty "Anomalies" table after job load

[elasticmachine]

Original comment by @pheyos:

Version:

• 6.2.0 BC3

Browser:

• Firefox 58.0, Chromium 63.0

Steps to reproduce:

• In Job Management click the button "Open in Anomaly Explorer" for a job
  • The Anomalies table should display all anomalies over all time, but sometimes the table is empty:
    
• If the table is filled:
  • Change back to Job Management and click the button "Open in Anomaly Explorer" for another job and look at the listed anomalies
  • Repeat for different jobs or the same jobs
  • In my setting after a few tries the table is empty in at least one of the iterations

Additional information:

• This does not happen every time the job is loaded. Switching between jobs seems to increase the likelihood of this issue to appear.
• This also happens (sometimes) when switching jobs via the job drop-down in the Anomaly Explorer

[elasticmachine]

Original comment by @walterra:

I'm removing the v6.2.4 label here, the issue is not a blocker and I wasn't able to reproduce the issue yet.

[walterra]

Fixed in #18717, backported until v6.3.0.