Bug in TTF-file

I’ve been using Fontself for a while and I’m having the same issues everytime I save and use a fontself-created font. For my font to cooperate with what I need for work, I have to convert the OTF-file to a TTF-file. And everytime I’m about to start using my new font there are different bugs showing. A few times the letters are mixed so like when I write an S on my keyboard a T shows, and so on. Usually it only takes that I reinstall the font and it corrects itself. Now when I klick on an already existing text the text makes a little jump to the right. Have tried to reinstall but it does not help. Can these bugs happen because I convert to TTF? Can it be that my Fontself is an old update- it says Fontself Maker 3.5.7 Is that the latest version? Or does anyone have the same issues or know how I can fix this?

Thank you!
Best Regards,

Weird. I have never had any problems with any of my fonts. It must be the TTF-conversion? What software are you using to convert the font?