Hi,
Some interface elements of our theme is designed for different font-weights. For example Regular (400), Semi-bold (600) and Bold (700), but custom font that you use didn’t support all them properly.
If you want to use proper custom web-font with several font-weight, in need to be served via several font-weight files. For example, if you want to use custom font Arial with font weights Regular (400) and Semi-bold(600) you need to find two files sets Arial-regular.woff/woff2, Arial-semi-bold.woff/woff2 and uploaded them to Custom Fonts like two fonts-weights with same name (screenshot https://prnt.sc/133wt86). Also, fonts-weights that assigned in Typography section must match font-weight that is uploaded to the Custom Fonts (screenshot https://prnt.sc/133wud1).
In case if you upload only one font-weight, other font-weights that is used in our theme will be replaced with fallback-weighs that will depend on operating system, browser and may look different depending on device or browser that you use. To make your font look the same in all browsers we suggest you to serve proper font-weights files for your custom font with support of Regular(400), Semi-bold(600) and Bold(700).
Kind Regards