I closed all apps by swiping up. Rebooted my iPhone/iPad and after the re-boot or soft-reset, all the apps are open again.
Hu??
for the last time: the "list" you see on ios when you double press the home button is not open apps, but "most recently used" apps. Whether that open is open in the background or no, is based on other rules which are outlined in Apple's developer doc. (https://developer.apple.com/library.../BackgroundExecution/BackgroundExecution.html).
So you're not necessarily "closing" anything. So why is it surprising if the list is the same after reboot?