You may face an issue where you're adding an inline CSS code to your text module and saving it but whenever you edit the module the inline CSS is being stripped out and tags (span and h tags tested) are converted to <p> tags.
This issue was resolved by the development team on 26 January 2022. If you face it again or a similar issue with different changes in tags, for example, please open a support ticket and provide the URL of the website where you’re seeing the issue, a reproduction video or screenshots of the issue, and the code you’re adding.
Refer to SCLOOPW-30057. If a similar issue happens again reproduce it in the demo environment and create a CDDS where you specify the change that happened to the code and add a reproduction video.