thanks for your reply!
I set my iOS devices to automatically download the newest versions of all apps. So the Evernote version is always the newest one, currently it's 7.14.
I usually create shortcuts only in the Windows version of Evernote on my PC at home or at work. The shortcuts remain untouched as long as I do not synchronise the content with any of my iOS devices.
As soon as I synchronise with iPhone or iPad, some of the shortcuts remain, some others disappear.
To be more precise, I have 5 shortcuts which I do not change frequently (let's call them A1..5), and 3 more shortcuts which I change frequently (B1..3)
Example: On Monday morning I delete shortcut B1 and create a new one (B4) instead. When I synchronize with iPhone on Monday afternoon, shortcuts A1..A5 remain and B2..B4 are gone.
Curiously, I cannot reproduce this behaviour when I synchronize the iPhone immediately after modifying the shortcuts. But several hours later the effect is reproduceable reliably. So it seems to have something to do with the age of the shortcuts and the timespan between creation and synchronization.
To clarify, no, all devices are correctly set to my local timezone, CEST.