Formbuilder translate is not supporting UTF

Formbuilder translation interface showing all letters as intended in UTF8.

But after saving the form letters become lie following

After bit of investigation i found translation .json file is in ASCII not UTF8 so tranlation is loosing letter as soon as file is created.

How do we change default behaviour to create .json in UTF8 ?

Thanks all

anyone ? please this issue should be easiliy solvable