Ubuntu 18.04 LTS - bold font in the browsers

I use Ubuntu 18.04 LTS. After the system installation all fonts was fine. Currently I have a bold font in the browsers (firefox and chrome) on almost every website. Please take a look on the example screen shot. In other apps, for example qtcreator or gedit fonts looks fine. I have tried the following command but without success:
Code:fc-cache -fvDo you have any idea how to fix that ?