Errors with a "does not exist" query

I am trying to determine if this is a bug before opening an Issue.

I am trying to create a query to return results when a field does not have any data.

These work and return results (but not what I'm looking for):

event.category:process and process.name:"rundll32.exe"
event.category:process and process.name:"rundll32.exe" and process.args:*
event.category:process and process.name:"rundll32.exe" and process.args_count>1
process.name:"rundll32.exe" and not process.args:*

I want to query when a process with a process name of rundll32.exe doesn't have any process arguments.

I've tried the following to only return processes but get an error each time:

event.category:process and process.name:"rundll32.exe" and not process.args:*
event.category:process and process.name:"rundll32.exe" and process.args_count<1

The error I get is:

Expected end of input but "n" found. process.name:"rundll32.exe" not process.args:* ----------------------------^

I have even tried to use a filter (process.args with a does not exist operator), same error.

This only appears to occur with the logs-* index pattern. The winlogbeat-* index pattern returns the expected results.

Kibana Version Platform Data Source Version
7.14.0 Elastic Cloud Winlogbeat & Elastic Agent (w/Window int.) 7.14.0

Logs-* (results, but not filtered to process)
process.name:"rundll32.exe" and not process.args:*

Logs-* (error, trying to only return processes)
event.category:process and process.name:"rundll32.exe" and not process.args:*

Winlogbeat (expected results, same query as Elastic Agent error)
event.category:process and process.name:"rundll32.exe" and not process.args:*

Hmm it looks like your error is coming from a query where you forgot to include "and" before "not".

Could you give this a try again?

event.category:process and process.name:"rundll32.exe" and not process.args:*

And see one more time if you get the same error about "expected end of input..."

I really don't understand...we have the same query that was getting errors yesterday - but now...not.

event.category:process and process.name:"rundll32.exe" and not process.args:*

I guess I'll just mark this as solved. Thanks!