I have a REST query which works as it should in SharePoint 2013 on-premise, but not in SharePoint Online.
The query is as follows (after encoding):
https://<tenant>.sharepoint.com/projects/1/_api/web/Lists(guid'37D38739-88BF-4EC4-B188-F334F88E2566')/Items?$expand=File&$select=FileRef,File/ServerRelativeUrl&$filter=startswith(FileRef,%27%2Fprojects%2F1%2FShared%20documents%2Ftestfolder1%2F%27)
If I remove the filter, I see all my files and folders in the result as expected. As soon as the filter is turned on, I get nothing. I can see from the the result when I don't include the filter that several items have the value I am attempting to filter on. Changing the filter to FileRef eq 'specific value' yields no results either.
Is it not possible to use filter on this field in SharePoint online?