Turning off "Maximize Compatibility" through the SDK

Ah, neat. I didn't realize that the presets are stored in easy to inspect files.  I was inspecting the table passed to an export filter plugin, where the setting does not appear. I can confirm your observation on the preset files.

Unfortunately, there still seems to be a problem setting it from a plugin.  I am now setting that key in the settings table:

function PtExport.export(photos)
  tempDir = os.tmpname()

  if #photos < 1 then
    return tempDir, {}
  end

  local isHdr = nil
  for _, photo in ipairs(photos) do
    local otherHdr = photo:getDevelopSettings()["HDREditMode"]
    if (isHdr == nil and otherHdr ~= nil)
        or (otherHdr ~= nil and otherHdr > isHdr) then
      isHdr = otherHdr
    end
  end
  
  local exportSettings = {
    LR_format = 'TIFF',
    LR_export_destinationType = 'tempFolder',
    LR_export_destinationPathPrefix = tempDir,
    LR_export_useSubfolder = false,
    LR_collisionHandling = 'overwrite',
    LR_renamingTokensOn = true,
    LR_tokens = '{{naming_operationSequence_5Digits}}',
    LR_extensionCase= 'lowercase',
  }

  if isHdr then
    exportSettings["LR_export_colorSpace"] = 'Rec2020_hdr'
    exportSettings["LR_export_bitDepth"] = 32
    exportSettings["LR_enableHDRDisplay"] = true
    exportSettings["LR_maximumCompatibility"] = false
  else
    exportSettings["LR_export_colorSpace"] = 'ProPhotoRGB'
    exportSettings["LR_export_bitDepth"] = 16
  end

  LrFileUtils.createDirectory(tempDir)

  -- Confirm the settings
  local file = io.open(tempDir .. "\\settings.txt", "w")
  if file then
    file:write(PtUtils.dump(exportSettings))
    file:close()
  else
    LrDialogs.message("Write Failure", tempDir)
  end


  local exportSession = LrExportSession({
    photosToExport = photos,
    exportSettings = exportSettings
  })
  exportSession:doExportOnCurrentTask()

  local outputFilenames = {}
  for i, rendition in exportSession:renditions() do
    outputFilenames[i] = rendition.destinationPath
  end
 
  return tempDir, outputFilenames
end

But it seems to be ignored.  I double checked the contents of the table:

$table: 000000034704FE90$ {
[LR_collisionHandling] = overwrite,
[LR_extensionCase] = lowercase,
[LR_export_useSubfolder] = false,
[LR_maximumCompatibility] = false,
[LR_tokens] = {{naming_operationSequence_5Digits}},
[LR_export_colorSpace] = Rec2020_hdr,
[LR_enableHDRDisplay] = true,
[LR_export_bitDepth] = 32,
[LR_export_destinationPathPrefix] = C:\Users\m_sto\AppData\Local\Temp\LR-11,
[LR_renamingTokensOn] = true,
[LR_format] = TIFF,
[LR_export_destinationType] = tempFolder,
} 

Anything I am doing wrong? Or a bug in Lightroom?

Martin