Hi,
According to this guide the contains function works on dataverse tables (former cds). According to documentation substringof should work for odata filter queries.
I get none to work.
Error: No function signature for the function with name 'contains' matches the specified arguments. The function signatures considered are: contains(Edm.String Nullable=true, Edm.String Nullable=true).
Error: An unknown function with name 'substringof' was found. This may also be a function import or a key lookup on a navigation property, which is not allowed.

This is on a ID column, the guid. Removing the single quotes also gives error.
I really didn't want to do another apply to each 😞