Other bucket not working on multiple aggregations

[Sjaak01]

Elastic cloud 6.4.2

If you make a visualization with two terms and enable grouping other values in separate buckets on them, the Kibana will trow this error:

Cannot read property 'map' of undefined

Disabling on of the groupings makes the error go away. This issue isn't present in 6.3.

[gmatheus]

I'm facing the same issue on 6.4.0 and 6.4.1 versions.

Steps to reproduce (using scripts/makelogs data):

• Create a vis with two terms and enable "Group other values in separate bucket" option on them (just as @Sjaak01 described)
• Choose a wide time range (e.g.: 1 day, 1 week, etc.). I couldn't reproduce the bug with the default "Last 15 minutes" config.
• In the first term bucket, choose a low "Size" value in order to force the use of "Other" feature for this aggregation level.
• Apply changes (sometimes you'll need to press refresh button as well)

Error: