Iron dysregulation and inflammatory stress erythropoiesis associates with long-term outcome of COVID-19, 2024, Hanson et al

I'm not sure that's why. I think the comma and the period are simply used in the opposite way (at least here in Hungary but I guess elsewhere too).

For example:

In English you would write 3.5 g, meaning 3 and a half grams. In some other countries this is 3,5 g because they use the comma in this context.

In English, you you would write 3,500 meaning 3500. In some other countries this would be 3.500, also meaning 3500. The period is optional though.

So they simply use the comma and the period differently but they use both.