I send out email notifications when new articles are posted on my site. Sometimes an email will have 3-4 links in it. The following format is used for the links:
When the user clicks on the link, they login before being redirected to the newest article, in this case, tID=7845. The sID is used to increment the number of clicks so we can keep track of how many times a particular keyword leads to actually reading posts.
Everything works great, most of the time. Some users are reporting that they click on the first link in the email, login, and view the new post. Then they click the second link in the email, and suddenly they get a blank white page with no error message. Some days these users can view all links fine, needing only to login the first time. Other days they can only read one post after logging in. I've seen it once myself, but usually I can't duplicate it. It has been seen in Safari, IE and Chrome. I'm not sure why no error message is shown at all, considering error reporting is turned on.
What on earth could be causing this sporadic crazy behavior?