Incorrect syntax highlighting in html template

[EnglederLucas]

Describe the bug
I am not getting the correct syntax highlighting on html template files. Non-standard-html elements are colored.

To Reproduce

1. Install Plugin
   Plug 'iamcco/coc-angular', {'do': 'yarn install --frozen-lockfile'} or
   Plug 'iamcco/coc-angular', {'do': 'yarn install --frozen-lockfile && yarn build'} (tried both)
2. Open angular (in my case) ionic html file

I also tried disabling coc-html with no success.

Expected behavior
I expected the correct syntax highlighting on custom elements

Screenshots

Desktop (please complete the following information):

• OS: Windows 10 x64
  Log: No logs

[年糕小豆汤]

No syntax highlight support by this extension.