Ubuntu – Ubuntu Server 18.04.2 HWE kernel: ./boot/grub/efi.img file failed the MD5 checksum when booting UEFI

I downloaded Ubuntu Server 18.04.2 (classic installer) and put it on a flash drive. I then ran the integrity check and all was well. But then I realized that I wanted to install the HWE kernel. After selecting HWE kernel, the installer start screen reloads, and I wondered if I would get a different result if I ran the integrity check with the HWE kernel.

Turns out it did, and the EFI.img file failed the MD5 check.
./boot/grub/efi.img file failed the MD5 checksum

I double checked the SHA256 of the iso I used to burn the USB (made with USB creator), and it was fine, so I figured I must have a bunk USB stick. I tried another stick (this time using dd copy method) and got the same problem. I then tried a third USB stick of a different brand (again using dd), and still the same.

So is there a problem in the installer itself? Or does the exact same file keep getting corrupted every time I try to create the bootable USB?

Edit: Ok, now I am really confused. It seems that efi.img file becomes corrupted at some point during the check. Here is a sequence of shots to illustrate:

1. I booted from the UEFI partition of my USB drive (oddly, on all the USB drives I have made today, there are two UEFI partitions seen by the BIOS, not sure if this is relevant).
2. Next I ran the integrity check in the main menu:
   
   it passed:
   
3. Then I went into the HWE kernel and tried the integrity check from there, which failed (the original reason for this post).
   
   
4. Then this is the real kicker.. now when I run the integrity check from the main menu, I get the same error!! Did the act of doing the check somehow cause corruption?
   
   

And one other thing: What is the "classic" keyboard based installer called officially? I don't know what to file the bug under since it doesn't seem to have a handy name like "Subiquity".

Update: If I select sandisk instead of sandisk: uefi partition, that does a legacy boot with a different looking main menu. However then I cannot create UEFI partitions in the manual partition editor. Perhaps the EFI section is in use to boot the usb and that is why checksumming fails? Is the classic installer even maintained anymore?