iOS 10.3.2: cookies will return after deletion. How to clean-up? I discoverd that in iOS 10.3.2 (german language set, timezone Berlin / MESZ) in my iPad not every information concerning history and tracking could be deleted:

Following Einstellungen (Setting), Safari, Erweitert (more or extended), Website-Daten (website data) there is a list of pages visited (I assume with cookies set). When I'm trying "delete all" none of the entries will disappear. I tried additionally deleting one by one. By entering this part of setting again (even without using safari in the meanwhile) there are some of the entries there again, some of them with 0 bytes. Resetting / rebooting iPad or cleaning history completely before deleting or combination of different steps cookies still are there.

Are the domains which are listed in some sense untrustworthy? Or do they use some "irregular" code / approach? The most persistant ones are


onedigitals.co.uk
parismatch.com
dove.com


Additional some google-domains (domains containing string google) and spiegel.de could be very often seen. Or some new sort of supercookies (but they are flash aren't they - and iOS does not support flash)? Or bug in iOS?

Perhaps related to
Also encountered the same problem on my iPhone 6s running iOS 10.3.2. There were some website data that could not be deleted and showed 0 bytes. It is definitely website specific as only a few domains keep popping up while others could be deleted. I tried rebooting my device, clearing safari history and manually deleting each cookie but nothing worked.
What fixed the problem was restoring my iPhone from a recent backup before I've visited the websites. I connected my iPhone to iTunes and clicked the 'Restore iPhone...' button on the device menu. After restoring, I set up my device from backup and all the unwanted website data were gone. Note that this may take a long time.