Web skin is not working in MetaRouter on RouterOS 6.5

Web skin is not working in MetaRouter on RouterOS 6.5,

Model 951G-2HnD
Current Firmware 3.10

When save new skin in webfig, the json file created under skins, but both webfig and system/users/groups can select the new skin, only default.

The skin works in my main router configs.

The skin works in main router and metarouter with RouterOS 5.26.