Hello Roddy2Hotty,
I have a 12 mini and still have the feature available. I also cannot find any setting that I believe would disable this. First, I would report this to Apple using https://reportaproblem.apple.com. Then,If you have not all ready I usually restart which fixes a lot of small one-off issues like the one you have. Restart your iPhone - Apple Support
After, I would speak with Apple Support directly. Get Support if it is not resolved from the restart.
In the mean time you may be able to get a full page screen shot the long way. Hit the middle share button at the bottom > then select the Books app. It will add a PDF of the entire website into your Library (you must have Include PDFs turned on in your Books App settings)
I hope this is helpful,