Detect Query Folding in model

Hi groongra,

Thanks for using Microsoft Fabric Community.

Like lbendlin  stated, it depends on data source. 
Query folding is supported by some data sources apart from Microsoft SQL server, Odata Feed,etc.
Check data sources here 
https://learn.microsoft.com/en-us/power-query/native-query-folding

It cannot be detected on bim file but some transformations may prevent query folding, please review the list below and check if there is any following transformation step in your query.

1.Merging/ appending queries based on different sources

2.Adding custom columns with complex logic.

3.Adding index columns.

Although this list is not exhaustive you can perform these checks to test where the query fails.

Additionally, you can go to https://learn.microsoft.com/en-us/power-query/query-folding-basics#sources-that-support-folding for more clarity.

Hope this helps.