Describe the bug

Any Chinese words cannot be typed into the BODY editor (see GIF below)

To Reproduce

1. Go to admin dashboard (<site_url>/admin)
2. Click on "New Blog"
3. Scroll down to the "BODY" editor area and type some Chinese words with default Chinese IME in Win10 (Microsoft Pinyin)

Expected behavior
see below

Screenshots

Applicable Versions:

• Netlify CMS version: netlify-cms-app 2.12.19
• Git provider: Github
• OS: Win10
• Browser version Chrome 87.0.4280.141

(My site was generated by the "Deploy to Netlify" Button in here, I'm using Gatsby template)

CMS configuration

all using default config