Graph Search API (/search/query) – NOT with free-text wildcard term does not exclude results, but NOT with property restriction does

We are using the Microsoft Graph Search API (POST https://graph.microsoft.com/v1.0/search/query) to list recently modified documents in a SharePoint Online folder. A free-text exclusion (NOT Trial)* does not exclude matching files. Scoping the exclusion to a property (NOT filename:Trial)* works as expected.

Folder contents (relevant files)

• KPI_Forecasting.xlsx
• DPO_DSO.xlsx
• Trial_Balance__06_2026.xlsx
• Trial_Balance__07_2026.xlsx
• Trial_Balance__08_2026.xlsx

Query 1 – exclusion with free-text term (NOT working as expected)

{
  "requests": [{
    "entityTypes": ["driveItem"],
    "query": {
      "queryString": "path:\"https://client.sharepoint.com/sites/Q1Reporting/Shared Documents/CFO Dashboard/Input Files/\" AND isDocument:true AND LastModifiedTime:2026-09-22T18:15:00..2026-09-29T18:15:00 AND NOT Trial*"
    },
    "fields": ["lastModifiedBy", "name", "webUrl", "lastModifiedDateTime"],
    "region": "ARE"
  }]
}

Expected: KPI_Forecasting.xlsx and DPO_DSO.xlsx only

Actual: all 5 files returned, including the three Trial_Balance files.

Query 2 – exclusion scoped to the filename property (working as expected)

queryString: same as Query 1, ending in "AND NOT filename:Trial*" instead of "AND NOT Trial*"

Result: only KPI_Forecasting.xlsx and DPO_DSO.xlsx returned.

We would like to understand why the free-text NOT behaves differently, since the KQL syntax reference states that NOT applies to both free-text expressions and property restrictions.