Combobox ListModel causes double-free scenario

Pressing "switch" on the attached minimal example crashes sometimes. Compiling with address sanitizer reveals a double-free scenario.

    =================================================================
  ==2699== ERROR: AddressSanitizer: attempting double-free on 0xf31a5220:
  #0 0xf69ba774 (/usr/lib/i386-linux-gnu/libasan.so.0.0.0+0x16774)
  #1 0xf5b9cc94 (/opt/qt/lib/libQt5Core.so.5.9.0+0x92c94)
  #2 0x13
  0xf31a5220 is located 0 bytes inside of 24-byte region [0xf31a5220,0xf31a5238)
  freed by thread T0 here:
  #0 0xf69ba774 (/usr/lib/i386-linux-gnu/libasan.so.0.0.0+0x16774)
  #1 0xf5b9cc94 (/opt/qt/lib/libQt5Core.so.5.9.0+0x92c94)
  previously allocated by thread T0 here:
  #0 0xf69ba854 (/usr/lib/i386-linux-gnu/libasan.so.0.0.0+0x16854)
  #1 0xf5b9cb23 (/opt/qt/lib/libQt5Core.so.5.9.0+0x92b23)
  #2 0xf5c07104 (/opt/qt/lib/libQt5Core.so.5.9.0+0xfd104)
    ==2699== ABORTING

The following characteristics are necessary to trigger the scenario, without either of them, the program runs fine:

• extraProperty in the model
• dependency in the visible for the Rectangle