It is not normal to see macrokaryotes in the brain. They are suggesting that it is due to vascular damage. Another way of looking at it is from a CNS model of covid, where the coronaviruses cause demyelination (what they are actually quite famous for). We know from past work that you can see this kind of atypical platelet / macrokaryote invasion as part of a cascade of repair systems in response to demyelination.

I posted it as it is yet another supporting bit of evidence for the coronavirus demyelination model of covid-19