When resending email for signing up, if users refresh the page, the content will be shown as below:
We sent another activation email to you at [missing {{currentEmail}} value] . It might take a few minutes for it to arrive; be sure to check your spam folder.
I can repro on Meta with Firefox and Chrome.
The email is missing because we delete user ID from session after sending activation email and that is indeed the correct/safe thing to do.
Considering this is an edge case (and can be reproduced by accessing /u/account-created/resent directly), I updated the code to show generic success message (on reload) as per:
https://github.com/discourse/discourse/commit/1381dc603d4dcad3c2ac6e12488692241fcbc79d