It may be that people are just less likely to report a stroke in VAERS, as time goes on. Whatever happens on vaccination day, will likely be suspected to be from the vaccine, but that subjective perception of association naturally drops over time.
It is a tiny percentage to study - a few hundred cases out of over 200 million shots. Reporting bias could account for it.
And purposefully so. Six months from now, I expect you people will blame all deaths on the covid and conveniently forget people got vaxxed, if what you are doing now is any indication.
Time is the friend of liars. Just ask the Clintons.