They specifically say those are natural, normal changes that happen with any virus and that so far the changes observed don't change anything with regards to the current vaccine developments etc.

Whether or not you interpret 84k genetic mutations as different strains or you believe their statement that the changes haven't impacted vaccine development is another matter. They won't be able to put out a vaccine with trials showing any efficacy if those are completely different strains. They're probably not that different, since coronaviruses are known not to change that much unlike influenza viruses which change a lot every year hence drive down the vaccine efficacy of flu shots.