I think this is a bug in iOS 15.0.x because it never happened to me before iOS 15; I'm at 15.0.2 now.
(1) When in Apple News, the back arrow (less than sign) at the top left often vanishes. I think it's turning from black to white on a white band across the top. I know it's still there because if I touch where it should be, I do go back. This was only a minor annoyance, until ...
(2) On Saturday I opened a parking pass in my wallet so I could see the address (a SpotHero parking pass). I left the pass open but went on to use my phone with Car Play and Apple Maps to get to where I was going. When I arrived, I went to show my pass to the lot attendant, and the QR code was gone. Just white background where the QR code use to be. No amount of swiping and fiddling could bring it back. I finally went to the SpotHero website, located my parking reservation, and used the "Add to Wallet" command again. The parking pass got reinstalled, and the QR code was visible again. I really don't think this is a SpotHero glitch; the pass had already been in my Apple Wallet for a month, and I had opened it and checked that it was there, and correct to use, with its QR code, several times over that time period.
Thank you for posting in the Apple Support Communities. It sounds like you have a couple of things going on since updating to iOS 15, correct? Both News and Passes were updated with iOS 15. As for your pass that was missing, it might have somehow been archived or removed with the update. If the issue happens again, we'd recommend reaching out to Apple Support.
As far as what you're seeing in the News app, it may be expected behavior in iOS 15 as you'd want to swipe from the left edge if you're in a story to return to the story list. We've included a link below for details.
Read stories in News on iPhone
Please let us know how it goes. We're always happy to help.
You're probably right about the pass being archived with the update; I've not had a problem since. Regarding the other issue, in Apple News, swiping from the left edge takes me to the previous story on that list, not the story list itself. I still prefer to use the back arrow at the top left to return to the story list -- and it still works for me, 95% of the time, it's just that it's white-on-white for some stories, about 5% of the time.