SIGMA rule translation -> lucene query replaces spaces " " with "_ws_" which lucene doesnt understand.

What is the bug?
A sigma rules with a whitespace gets incorrectly translated to a search query with "ws" instead of a whitespace.

How can one reproduce the bug?
detection:
condition: (selection and selection_evt) and not filter_main_known_locations
filter_main_known_locations:
process.executable|contains:
- C:\Program Files (x86)\Windows Defender\
- C:\Program Files\Microsoft Security Client\
- C:\Program Files\Windows Defender\
- C:\ProgramData\Microsoft\Windows Defender\Platform\
- C:\Windows\WinSxS\
selection:
process.name:
- MpCmdRun.exe
- NisSrv.exe
selection_evt:
event.code: 1
event.module: sysmon

Results in:
(((process.name: "MpCmdRun.exe") OR (process.name: "NisSrv.exe")) AND ((event.code: 1) AND (event.module: "sysmon"))) AND ((((NOT process.executable: C:\Program_ws_Files_ws_(x86)\Windows_ws_Defender\ AND exists: process.executable) AND (NOT process.executable: C:\Program_ws_Files\Microsoft_ws_Security_ws_Client\ AND exists: process.executable) AND (NOT process.executable: C:\Program_ws_Files\Windows_ws_Defender\ AND exists: process.executable) AND (NOT process.executable: C:\ProgramData\Microsoft\Windows_ws_Defender\Platform\ AND exists: process.executable) AND (NOT process.executable: C:\Windows\WinSxS\ AND exists: process.executable))))

What is the expected behavior?
A whitespace should work properly in a sigma rule that is translated to a lucene query

What is your host/environment?
OS 2.13

Do you have any additional context?
Looking in github, I can see where the "ws" is being set. Not sure why.
https://github.com/search?q=repo%3Aopensearch-project%2Fsecurity-analytics%20%20_ws_&type=code