Kibana version:
7.6.1

Elasticsearch version:
7.6.1

Server OS version:

Browser version:
Chrome 81.0.4044.129

Browser OS version:
macOS Catalina 10.15.4

Original install method (e.g. download page, yum, from source, etc.):
Elastic Cloud

Describe the bug:
The name of the signal's rule (signals.rule.name) is not showing on the expanded (detailed) table of the signal. JSON View shows the name correctly.

Steps to reproduce:

1. Go to SIEM -> Detections -> Signals (Table at the bottom of the page).
2. Click the arrow at the left of the timestamp.
3. Go to the signals.rule.name. The value of the fields is - where it should be the name of the rule.

Expected behavior:
It should show the name of the rule correctly.

Screenshots (if relevant):

Errors in browser console (if relevant):

Provide logs and/or server output (if relevant):

Any additional context:
I reproduce the bug on master.