I've found keystrokes in Vietnamese (not English) behave very weird with Gmail and Google Sheet in Firefox browser. They don't happen with Chrome browser (in the same situations): -You can't delete the characters you already typed if you insert the cursor between them. -If you delete some words then retyping, it makes double characters. -Sometimes when you type the period (.), the previous word just disappears. You have to type a space before you can put a period. Those have been happening a couple of months. My Firefox browser version is 112.0.2 (64-bit)