Hello,
I think I get the problem the chrome navigator use some cash to display some page when the url is the same.
So, theorically that's mean that data was updated, and Paypal sends refresh data page BUT Chrome display the page from his cash (in memory)!
So, I add unix time as an hash in redirect url, to make each of them unique, I test it and it seems that works.
In attachement the new paypal version that must solve this.
Awaiting news from you and like already told thanks for your return.
Regards.