Power BI v2.85.681.0+(and above) is throwing a query folding error on direct query to postgresql data connections that is not present on the August 2020 version of power bi:
August 2020 Build:
September 2020+ Build (exact same report)
more details of the errors can be found here: https://community.powerbi.com/t5/Desktop/Power-Bi-v2-85-681-0-Breaking-a-Working-Report-Direct-Query...
The latest version 2.85.985.0 64-bit (September 2020) works fine for me. Try to recreate the report.
@v-chuncz-msft Thanks. So I rebuilt the report and realised that the code to create a calcualted column works in August but fails in September. I re-wrote that query and it's all fine now. Thanks!