I have found a seed that when pulled from windows10 edition and played on MCPE doesn't generate End Cities.

Device: HTC Adreno (HTCD160LVWPP Adreno (TM) 304

Steps to reproduce:
1: Start a new game on Creative mode.
2: insert Seed 1932870991 where it says Seed.
3: find the Stronghold.
4 find and go through the End portal.
5: Fight the Ender Dragon.
6: Go through the portal taking you to the islands where the end cities are supposed to spawn and fly around in creative mode and try to find an end city.

Note:I haven't tried this with any other seeds but I am sure if it happens with one seed pulled from Windows 10 edition it happens with others as well.