Steps to reproduce the issue

Create an article. Type something in the content. Select save. Type "Edit" to return to enter edit mode for the same article.
Type some words to update the article. Then select save.
The system shall spin during saving process.
Please note the duration of the spinning time. Instantly or 3~5 seconds.
Make sure your article is saved with new update.
If not, user will have to select "<--" (Back button) on the browser to return to the article in editor mode, and select save again.
The system shall save properly as the system shall spin longer during saving process.

Expected result

System shall spin for a few seconds during saving process

Actual result

Occasionally, system spin for one second and jump out of editor mode

System information (as much as possible)

• Joomla 4 is hosted on Ubuntu 21.04
• This issue happens since the beginning of 4.0.x version.
• The issue is NOT related to Editor (TinyMCE or JCE) or Browser (Google Chrome of MS Edge).
• The bug may not happen in the first attempt. Try it for 10 times, you will definitely get one.
• To work around this bug, the user will need to use the browser back button (<--) to return to the page in which the article is in the edit mode and with the update. Select "Save" to save the article again. The article shall be saved for the second time.

Additional comments

You may contact me at bkwchong@gmail.com, Bryan Chong.