The story about late Neandertals near the Arctic circle in Russia, is contentuous. The point is, that it heavily hinges on an assumed equation of particular tool types with a particular hominin species: which in this case is not warranted.
While Neandertals did use Mousterian tools, Homo sapiens is known to have used them as well, up to 45,000 years ago and possibly later on some occasions. On the Russian plain, some 1000 km south of this near-Arctic site, there are sites which have both Mousterian type tools along with Upper Palaeolithic type tools. And there are reasons to think this is not due to later mixing of layers. The suggestion here is hence, that Homo sapiens pioniers in these northern Russian areas used a toolkit combining Mousterian tools with UP tools, the latter of a type so far only associated with H. sapiens. In some cases, they might have used a Mousterian toolkit only. Finding Mousterian tools in such a situation, hence does not rule out H. sapiens as their maker. The surprisingly young age (for Neandertals) gives additional reasons to doubt. Untill a Neandertal skull is found there, I’d say it is far from certain who made these tools - could well be H. sapiens instead of Neandertals.