When I used the back button to navigate away from the CSC chance game, it drew a second item (and took my CSC). I don't know why this happened and I did not test it again to see how long it would go on for. Beware :0

This happens for the vending machines as well. It's been like that for years. Just don't use the back button on them until things are resolved.
75 CSC is worth a little bit more than 2 wizard tokens, so it's not quite as excusable

Yeah, that's quite a mishap. You can file a ticket. It's reasonable enough to do so in my opinion. Not everyone has the luxury of navigating freely, especially on the phone.
They must have shared the same code and issues together.
Why exactly would you use the back button to go away from the page rather than just using navigation? I'm curious!
I do suggest filing a ticket about it and having a UA help you out on this, I've already let them know they'll likely be getting a ticket about it! is correct, that all the vending machines use the same basic code (the same way most quest givers use the same code). I'll let a programmer know this is a thing, as well.
Cause the back button is so easy to use, and it's just right there! ;)
I've seen a fair amount of boomers who kept complaining about the back button not doing what it's intended, and then using it again when advised not to.
here's the thing. functionally, from a server perspective, there is no difference between you hitting your back button and you manually refreshing the page. you hit the back button, your browser loads the last page you were on. and there are far more people who want to be able to do an action again by refreshing than there are people who use their back button to navigate. we have put the functionality in features before that disabled the back button repeating the action, but that also disables refreshing. it's really just an either/or situation.
the answer is really just don't use your back button to navigate subeta. but yes when an action gets repeated because you used your back button you can always file a ticket and a ua can help you out.
Is this still problematic with HTML5 and AJAX that Subeta uses? (The "AJAX Back Button Hash" search results might have some information about this)
I was just trying to get back to the news post that sent me to the machine. I figured since I'd only clicked it once, the last page I was on was just the welcome screen for the machine.
ETA I did send in a ticket and it's being resolved. I just wanted to get a warning out there for other lazy back-button users like me

honestly, having not personally coded or even looked with anything on subeta that uses that functionality at all, i can't say because i don't actually know how they're set up to use ajax and things. i'll have a look at it, but it might not be for a week or so.