Being prompted to use Redeem code with Testflight Public Sharing link

Question

I have been sharing a public link for my testflight app and whilst some users are able to download without any problems, others are prompted by testflight to add their redeem code (Which I cannot find anywhere) Anyone know why?

Here's the link https://testflight.apple.com/join/EyUDjsLx

Thanks Andrew

Answer 1

I've noticed this issue as well. What worked for me was : having the user click the link again, AFTER installing testflight

Answer 2

Close TF app and reopen it. The app should wait there for you to install.