Pkg.test demo GUI "back" functionality unpredictable

[CrashBurnRepeat]

When using the Pkg.test demo GUI, I have tried to view previous demos with the back button (not the back to beginning button) but instead of loading the previous test, it will load one of the earliest demos. The REPL output looks like this:

Now showing playslider.jl:

WARNING: replacing module hybrid
Now showing hybrid.jl:

Now showing contourf.jl:

where playslider.jl is one of the demos in the middle of the series, and hybrid.jl is, I believe, the second. Clicking on next button seems to pick up in the correct location, as also shown in the REPL output here. I have called the behavior unpredictable since, on other attempts, I've ended up on the first demo as well.

System information:
Graphics/Displays:

Intel HD Graphics 530:

  Chipset Model: Intel HD Graphics 530
  Type: GPU
  Bus: Built-In
  VRAM (Dynamic, Max): 1536 MB
  Vendor: Intel (0x8086)
  Device ID: 0x191b
  Revision ID: 0x0006
  Automatic Graphics Switching: Supported
  gMux Version: 4.0.29 [3.2.8]
  Metal: Supported

Radeon Pro 460:

  Chipset Model: AMD Radeon Pro 460
  Type: GPU
  Bus: PCIe
  PCIe Lane Width: x8
  VRAM (Total): 4096 MB
  Vendor: ATI (0x1002)
  Device ID: 0x67ef
  Revision ID: 0x00c0
  ROM Revision: 113-C980AF-908
  Automatic Graphics Switching: Supported
  gMux Version: 4.0.29 [3.2.8]
  EFI Driver Version: 01.00.908
  Metal: Supported
  Displays:
    Color LCD:
      Display Type: Built-In Retina LCD
      Resolution: 2880 x 1800 Retina
      Pixel Depth: 32-Bit Color (ARGB8888)
      Main Display: Yes
      Mirror: Off
      Online: Yes
      Rotation: Supported
      Automatically Adjust Brightness: No
      Connection Type: DisplayPort

Hardware:

Hardware Overview:

  Model Name: MacBook Pro
  Model Identifier: MacBookPro13,3
  Processor Name: Intel Core i7
  Processor Speed: 2.9 GHz
  Number of Processors: 1
  Total Number of Cores: 4
  L2 Cache (per Core): 256 KB
  L3 Cache: 8 MB
  Memory: 16 GB
  Boot ROM Version: MBP133.0226.B25
  SMC Version (system): 2.38f7

Memory:

Memory Slots:

  ECC: Disabled
  Upgradeable Memory: No

    BANK 0/DIMM0:

      Size: 8 GB
      Type: LPDDR3
      Speed: 2133 MHz
      Status: OK
      Manufacturer: 0x802C
      Part Number: 0x4D5435324C31473332443450472D30393320

    BANK 1/DIMM0:

      Size: 8 GB
      Type: LPDDR3
      Speed: 2133 MHz
      Status: OK
      Manufacturer: 0x802C
      Part Number: 0x4D5435324C31473332443450472D30393320

NVMExpress:

Apple SSD Controller:

    APPLE SSD SM1024L:

      Capacity: 1 TB (1,000,555,581,440 bytes)
      TRIM Support: Yes
      Model: APPLE SSD SM1024L
      Revision: CXS6AA0Q
      Link Width: x4
      Link Speed: 8.0 GT/s
      Detachable Drive: No
      BSD Name: disk0
      Partition Map Type: GPT (GUID Partition Table)
      Removable Media: No

Software:

System Software Overview:

  System Version: macOS 10.12.6 (16G29)
  Kernel Version: Darwin 16.7.0
  Time since boot: 8 days 1:51