Font doesn't remain consistent when adding text to an existing Type Toolbox

I created a Type Tool text box, changed the font to the one I wanted, and typed in my text. However, I’m facing two problems:

1. When I try to add more text inside the same text box, the font weight doesn’t stay the same. For example, if the font was set initially to Bold, but when I add new text, the new text I added changes to Medium automatically.

2. The font style changes when I switch to another language and start typing. The font settings I applied disappeared, and the text switched to a different style, even though the font I’m using supports both languages.

Please let me know how I can fix these issues.