If you use thegenerateKey to customize a filename before uploading a file to S3, the newly generated filename is then ignored and not properly propagated back to the Parse Server to be stored in the fields referencing that file.

The only way to make thegenerateKey option work is to turn on ParseServerpreserveFilenames option that will leave all the logic of generating proper file names on the client.

Seeparse-community/parse-server#6518

The proposal would be to modifyvalidateFilename in file adapters to not return error but rather a modified filename. That can in turn reuse thegenerateKey option.