plugin/* not loaded when nvim {file}

[epheien]

• nvim --version: 0.10
• git --version: 2.24.3
• Operating system/version: macOS Catalina 10.15.7 19H2026 x86_64
• Terminal name/version: alacritty

Steps to reproduce

• $ mkdir plugin1/plugin -p
• $ echo 'echomsg "helloworld"' > plugin1/plugin/x.vim
• $ mv plugin1 pckr/opt/ # move to where pckr opt dir (local plugin seems not work)
• add plugin spec:

    {
      'xxx/plugin1',
      cond = event('FileType'),
    };

• $ touch a.go
• $ nvim a.go
• :mes

Actual behaviour

no message

Expected behaviour

one messsage:
helloworld

pckr files

Plugin specification file(s)

    {
      'xxx/plugin1',
      cond = event('FileType'),
    };