flyback converter common-mode surge 6kV issue

I am solving a 10W flyback to pass the differential mode and common mode 6kV surge tests. Currently, the differential mode 6kV PASS , but the controller IC will be broken when testing the common mode 6kV, and only the IC will be damaged. IC is TNY286

The PCB Layout complies with the suggestion of TNY286, but I saw that the Layout suggestion of TNY288 is different, and I try to change it to the Layout suggestion of TNY288, the common mode 6kv surge is PASS.

I think you need to correct the layout suggestion of TNY286. I don’t know any reason not to change it to the layout suggestion of TNY288. Can you explain the reason why TNY286 is not changed to star grounding? What are your considerations?

TYN286 ref:

https://www.mouser.tw/datasheet/2/328/tinyswitch_4_family_datasheet-1511375.pdf

TNY288 ref:

https://www.power.com/downloads/documents/rdr-839_12watt_power_supply_using_tinyswitch-4.pdf