Hi,
If you have access to 2 LISN, I would recommend to get a Schwarzbeck CMDM 8700. This device let you separate the CM and DM noise. A very nice tool, but not everybody has 2 LISN laying around to use it.
Regarding what you are measuring, here is what I think:
- Choke on PE should be avoided
- If the CM choke is not providing enough saturation, it might be saturating, or simply does not provide enouh attenuation at 300kHz.
From what I see it could be a DM noise coming from L1 but not with L2. Maybe a single phase load ?