seems i have found the reason for these errors. will update this if the error comes back.
if you use firefox, check if it is using the latest version of the flash add-on.
you can see that by clicking the hamburger menu in firefox top right. the cleck addons, and look in plugins. you see the flash plugin there, now click that.
when all is correct you will see only the latest version of the flash plugin.
the problem with flash is that when you update inside firefox to latest version of flash it will install the new version but it is not removing the old plugin.
this results in firefox to use both old and new version, giving unexpected beheivour.
the solution is easy.
first clear firefox cache.
open explorer and go to
you will see that flash has not removed any of the old version (*.dll)
keep only files there that start with the same name and extension with the last numbers are highest. delete the others.
now start firefox again and you should see the last version is used and no more multiple instances.