Hi Gautam,
Sorry for the inconvenience caused. RichTextEditor relies on Web-view, the reported issue occurs only with the ‘Gboard’ as keyboard and it also occurs in the default content editable div element.
But we have logged this issue report to Google, please check the below link for reference,
We will observe closely on this issue and let you know once the issue is fixed by Google.
Note: This issue occurs only in lower Android version and Its working fine properly in Higher Android version.
With Regards,
Gayathri R