My family switched to iCloud (and Safari, from Firefox) specifically for this feature on iOS and Mac, and while it's always been a bit glitchy for me, I assumed they were tweaking it as part of the ongoing beta.
Lately, as I continue to have to turn it off for many websites, I'm starting to think Apple has given up on consistently improving the product, or at least getting it stable enough. A brief search for recent news or updates from Apple has me suspecting this is true. Thanks for any thoughts.