Why is Apple adding RFC5322 spam headers? x-spam-flag: yes x-suspected-spam: true

I am a mail developer and in my testing with correct SPF, DKIM and DMARC results, upon reception of mail, apple is adding two headers:

x-spam-flag: yes

x-suspected-spam: true

All SPF, DKIM, DMARC headers and Authentication-Results are passing,

Authentication-Results: dmarc.icloud.com; dmarc=pass header.from=XXXXX.XXX. ...

Authentication-Results: dkim-verifier.icloud.com; dkim=pass (2048-bit key). ...

Authentication-Results: spf.icloud.com; spf=pass. ...

Received-SPF: pass (spf.icloud.com: ...

Everything passes. So how does it make it a suspected spam?