Welcome to the Microsoft Q&A Platform. Thank you for reaching out & I hope you are doing well.
- Can you confirm Compression is enabled on the AFD?
- Can you please share a screenshot of the Rule?
- It is possible that Compression is disable on the AFD and the Origin is actually the one responding with compressed content.
See : There are two ways to enable file compression
- Enabling compression on your origin server. Azure Front Door passes along the compressed files and delivers them to clients that request them.
- Enabling compression directly on the Azure Front Door POP servers (compression on the fly). In this case, Azure Front Door compresses the files and sends them to the end users
Cheers,
Kapil