Designer 2017 crashes when trying to delete hidden callout

Some callouts were Broken Apart so I was trying to replace a callout by drawing a new one over the top of the existing one, and then deleting the one in the back.

To reproduce this bug, all I do is:

  1. Draw a callout (we use custom callouts with a halo and custom arrow)
  2. Right-click Break Callout Apart
  3. Draw another callout over the top of existing one
  4. Ctrl+Alt+click the callout line (to select the thing behind the newest callout)
    (Notice nothing is selected in the Object Manager)
  5. Press Delete
  6. Crash