For context, because Scotland is so big and empty, a disproportionate chunk of UK wind power is based there compared to their population - so much so that if I remember correctly their wind power has to curtail sometimes due to interconnect limits with the rest of the UK. It's kind of hard to get day-by-day or hour-by-hour figures for Scotland alone, but Scottish nuclear + renewables in the entire UK dropped well below Scotland's peak demand a good few times just in the last two months. That shortfall has to be made up using fossil fuels, there's no alternative - and a good chunk of that is going to be Scottish fossil fuel plants due to interconnect limits.
The Scottish government is simply using the fact that a disprortionate amount of UK wind power ended up there to spin themselves as less dependent on fossil electricity than they are. You can't measure progress towards an 100% grid using net figures like this because the last bit of demand is so much harder to satisfy renewably than the first, and countries with the ability to play silly tricks like this with net power can skip the hard part and pretend they've solved the problem. If/when renewable generation in England and Wales increases it might well even roll this figure back as less electricity is imported during peak wind generation, despite the fact that both Scotland and the rest of the UK would be getting more of their actual electricity from renewable sources.