Hey Christin, thank you for flagging! It looks like your issue is similar to another one we were tracking, and a fix has now been released.
Please try reloading the tab you’re working in, and font weights should now behave as expected.
If you’re still seeing the problem, please reach out to our Support team with a screen recording that shows the entire Figma window and all the steps leading to the issue. You can submit it here: Submit a request
These videos are super helpful for our team to reproduce the problem and make sure it’s fully resolved, thank you!