Dolphin (file manager) renaming other files when copying a file

I opened Dolphin in a directory with a lot of large (video) files. I then created another Dolphin window of another directory (on the same file system.) I proceeded to move files from one to the other. Because the pop-up menu gets old quickly I held down Shift to make sure I got move behaviour without the pop-up.

Expected Result: The file "old/A.mp4" is moved to "new/".
Actual Result: The file "old/A.mp4" is correctly moved to "new/A.mp4"
   But in addition, some random "old/B.mp4" has been silently renamed "old/A.mp4"

This happened twice. I've "refreshed" dolphin and it seems the change is real in the filesystem, not just an error in the display.

I believe this is a serious bug, as it has result in data loss (ie the file B has lost its name)

Workaround: just use the pop-up menu

Description: Ubuntu 18.04.3 LTS
Release: 18.04

dolphin:
  Installed: 4:17.12.3-0ubuntu1
  Candidate: 4:17.12.3-0ubuntu1
  Version table:
 *** 4:17.12.3-0ubuntu1 500
        500 http://gb.archive.ubuntu.com/ubuntu bionic/universe amd64 Packages
        100 /var/lib/dpkg/status