failing Install /e/ on Motorola Moto G 2015 - "osprey"

Summary

Final install of ROM.zip by TWRP fails for Motorola Moto G 2015 - "osprey": Instead of loading /e/, Motorola shows Warning Bootloader Unlocked.

Steps to reproduce

&

What is the current behavior?

It seemed that my Install /e/ on Motorola Moto G 2015 - "osprey" was going well, up until the very last point.

So Unlocking the bootloader and Installing a custom recovery (twrp-3.3.0-0-osprey.img) went good. Then I needed Installing /e/ from custom recovery which worked not by sideloading (see below), but instead copying the ROM via an SDcard.

Then in TWRP I did Install, chose the ROM: e-0.5-n-201904167346-dev-osprey.zip. Result:

Then I click Reboot System (either with or without first clicking Wipe Cashe/Dalvik). The result is the standard motorola warning:

What is the expected correct behavior?

I expected to see the /e/ startup screen and startup sequence happening.

I tried this several times, always with the same result.

I have asked for and received help in the community: Moto G 2015 - “osprey” - Build? , but so far I did not manage to fix.

Another minor issue: Sideloading the ROM.zip does not work: on the PC, it runs until 47%, then breaks off. Tried this several times. So instead I have copied the ROM.zip to a SDcard, then copied from there to the phone, internal folder "/sdcard", right under /TWRP.