Samsung predictive text issue

I have a bug to report. On some Samsung devices, the predictive text feature of keyboard repeats input inserted into a webpage. It happens with Firefox only.

 

Here’s a use case I am working on
User needs to enter mobile number in text field of html form. When the input changes the reactJS handler checks the input value and removes non-digit characters. So If a user types 12ss it becomes 12. But while using Samsung keyboard’s predictive text feature, typing 12ss actually becomes 1212.

 

Device: Samsung Galaxy A51 (but not only this, a few more have this issue)
Model: SMA51-5F
Browser: Firefox 80.1.1
OS: Android 10
Kernel: 4.14.113

 

Here is a demo page: https://repl.it/talk/share/Samsung-bug/87218 2
The line below input field, shows what value is coming from keyboard

Here is a recording: https://youtu.be/qHkl9RhEp6E 1