An issue with Source Sans is that there are differences in the designation of the individual font styles on different systems (Windows, MacOS, etc.). In one system, for example, “semibold” is referred to as “halbfett” and vice versa. This can lead to preset “text styles” in the templates (e.g., in Affinity) to not being interpreted correctly. If this happens to you, unfortunately you will have to correct the setting or the assignment of which font style should be used yourself.