ISO Disc Image to MP4 Fails only when using Queue [handbrake]

Question

I'm using the latest Handbrake portable version, I haven't changed any settings other than selecting 'Web Optimized'.

I have a folder full of .ISO files (home movies converted from vhs, unencrypted), when I select one file at a time I am able to convert them great. When I choose folder and add all to Queue, the first ISO file will convert, but each file after that will quickly fail.

Here is the log of the 2nd file (failed):

HandBrake 1.5.1 (2022011000)
OS: Microsoft Windows NT 10.0.22000.0
CPU: 11th Gen Intel(R) Core(TM) i3- @ 3.00GHz
Ram: 7934 MB, 
GPU Information:
  Intel(R) UHD Graphics - 30.0.100.9864
Screen: 1536x864
Temp Dir: C:\Users\x\AppData\Local\Temp\
Install Dir: C:\Users\x\Downloads\HandBrake-1.5.1-x86_64-Win_GUI\HandBrake\
Data Dir: C:\Users\x\AppData\Roaming\HandBrake

-------------------------------------------

 # Starting Encode ...

[13:35:33] base preset: Fast 1080p30
[13:35:33] Remote Process started with Process ID: 12816 using port: 8037. Max Allowed Instances: 1
[13:35:41] Worker: Starting HandBrake Engine ...
[13:35:41] Worker: Starting Web Server on port 8037 ...
[13:35:42] Worker: Disconnected worker monitoring enabled!
[13:35:42] Compile-time hardening features are enabled
Cannot load nvEncodeAPI64.dll
Cannot load nvEncodeAPI64.dll
Cannot load nvEncodeAPI64.dll
Cannot load nvEncodeAPI64.dll
[13:35:42] hb_init: starting libhb thread
[13:35:42] Starting work at: Wed Dec 07 13:35:42 2022
[13:35:42] 1 job(s) to process
[13:35:42] json job:
{
  "Audio": {
    "AudioList": [
      {
        "Bitrate": 160,
        "DRC": 0,
        "Encoder": "av_aac",
        "Gain": 0,
        "Mixdown": 4,
        "NormalizeMixLevel": false,
        "Samplerate": 0,
        "Track": 0,
        "DitherMethod": 0
      }
    ],
    "CopyMask": [
      "copy:aac",
      "copy:ac3",
      "copy:dtshd",
      "copy:dts",
      "copy:eac3",
      "copy:flac",
      "copy:mp3",
      "copy:truehd",
      "copy:mp2"
    ],
    "FallbackEncoder": "ac3"
  },
  "Destination": {
    "ChapterList": [
      {
        "Name": "Chapter 1"
      }
    ],
    "ChapterMarkers": true,
    "AlignAVStart": true,
    "File": "C:\\Users\\x\\Videos\\xyz.m4v",
    "Mp4Options": {
      "IpodAtom": false,
      "Mp4Optimize": false
    },
    "Mux": "av_mp4"
  },
  "Filters": {
    "FilterList": [
      {
        "ID": 4,
        "Settings": {
          "mode": "7"
        }
      },
      {
        "ID": 3,
        "Settings": {
          "block-height": "16",
          "block-thresh": "40",
          "block-width": "16",
          "filter-mode": "2",
          "mode": "3",
          "motion-thresh": "1",
          "spatial-metric": "2",
          "spatial-thresh": "1"
        }
      },
      {
        "ID": 13,
        "Settings": {
          "crop-bottom": "0",
          "crop-left": "12",
          "crop-right": "0",
          "crop-top": "0",
          "height": "480",
          "width": "708"
        }
      },
      {
        "ID": 6,
        "Settings": {
          "mode": "2",
          "rate": "27000000/900000"
        }
      }
    ]
  },
  "PAR": {
    "Num": 8,
    "Den": 9
  },
  "Metadata": {},
  "SequenceID": 0,
  "Source": {
    "Angle": 1,
    "Range": {
      "Type": "chapter",
      "Start": 1,
      "End": 1
    },
    "Title": 2,
    "Path": "D:\\xyz.ISO"
  },
  "Subtitle": {
    "Search": {
      "Burn": true,
      "Default": false,
      "Enable": true,
      "Forced": true
    },
    "SubtitleList": []
  },
  "Video": {
    "Encoder": "x264",
    "Level": "4.0",
    "TwoPass": false,
    "Turbo": false,
    "ColorMatrixCode": 0,
    "Options": "",
    "Preset": "fast",
    "Profile": "main",
    "Quality": 22,
    "QSV": {
      "Decode": false
    }
  }
}
[13:35:42] CPU: 11th Gen Intel(R) Core(TM) i3- @ 3.00GHz
[13:35:42]  - Intel microarchitecture Tiger Lake
[13:35:42]  - logical processor count: 4
[13:35:42] Intel Quick Sync Video support: yes, gpu list: 0
[13:35:42] Intel Quick Sync Video integrated adapter with index 0
[13:35:42]  - Intel Media SDK hardware: API 1.35 (minimum: 1.3)
[13:35:42]  - Decode support:  h264 hevc (8bit: yes, 10bit: yes) av1 (8bit: yes, 10bit: yes)
[13:35:42]  - H.264 encoder: yes
[13:35:42]     - preferred implementation: hardware (1) via D3D11
[13:35:42]     - capabilities (hardware):  breftype icq+la+i+downs vsinfo opt1 opt2+mbbrc+extbrc+trellis+ib_adapt+nmpslice
[13:35:42]  - H.265 encoder: yes (8bit: yes, 10bit: yes)
[13:35:42]     - preferred implementation: hardware (1) via D3D11
[13:35:42]     - capabilities (hardware):  lowpower bpyramid icq vsinfo opt1
[13:35:42] hb_scan: path=D:\xyz.ISO, title_index=2
src/libbluray/disc/disc.c:437: error opening file BDMV\index.bdmv
src/libbluray/disc/disc.c:437: error opening file BDMV\BACKUP\index.bdmv
src/libbluray/bluray.c:2646: nav_get_title_list((null)) failed
[13:35:42] bd: not a bd - trying as a stream/file instead
libdvdread: Encrypted DVD support unavailable.
libdvdnav: DVD Title: XYZ
libdvdnav: DVD Serial Number: 1468DC55DVDSHR_XYZ
libdvdnav: DVD Title (Alternative): 
libdvdnav: DVD disk reports itself with Region mask 0x00c00000. Regions: 01 02 03 04 05 06
libdvdread: Encrypted DVD support unavailable.
[13:35:42] scan: DVD has 1 title(s)
[13:35:42] scan: scanning title 2
[13:35:42] Invalid VTS (title set) number: 0
[13:35:42] libhb: scan thread found 0 valid title(s)
hb_dict_to_job: Title 2 doesn't exist
[13:35:42] Finished work at: Wed Dec 07 13:35:42 2022
[13:35:42] libhb: work result = 3

 # Job Failed to Initialise. Check log and input settings (3)