If I set my spawn at a bed in the overworld, then enter the End and go back through the exit portal without closing the world, I return to the overworld at my bed. If, however, I enter the End, close the world, restart in the End, and enter the Exit portal, it sends me back to the world spawn with the message that my bed is missing or obsteucted. This is, of course, very inconvenient as I am then far away from my bed spawn.

I have used commands to teleport back to the bed and verify that it exists and is not obstructed. If I reset my spawn on the same bed, enter the End, and exit immediately, I spawn back at the bed. But if I close and reopen the world while I'm in the End, I will spawn back at the world spawn.  

This is consistently reproducible, and happens both on Android and on desktop/Windows 10. I have tested this on two separate stronghold End portals, with different bed placements. Currently I am at the stronghold located at -2300,1476 in seed -775501438.

Thank you for the 1.18 update. It's awesome