Post Process Export Plugin Help Needed

I have been banging my head on this for a good day or so, so looking for some help.

I have a Plugin which I need to do some metadata tweaking when images are exported.  The code (see below), sems to work and returns the expected results to the logfile, but the export doesn't continue and no image is exported.

Can anyone see what I am doing wrong or missing ?

Thanks

local LrLogger = import 'LrLogger'
local LrTasks = import 'LrTasks'
local LrApplication = import 'LrApplication'
-- Simple logger initialization for testing
local logger = LrLogger("TestPostProcessActionProvider")
logger:enable("logfile")  -- Ensure it logs to Lightroom's log file
logger:info("Plugin has started executing")

return {
    sectionForFilterInDialog = function(viewFactory, propertyTable)
        return {
            title = "Update IPTC:Headline with Title",
        }
    end,

    postProcessRenderedPhotos = function(functionContext, exportContext)

        logger:info("Post-process action triggered")

            local success, err = LrTasks.pcall(function()

                if not exportContext then
                    logger:error("Export context is invalid or missing.")
                    return
                end        

                    for sourceRendition, renditionToSatisfy in exportContext:renditions() do

                        LrTasks.startAsyncTask(function()
                            local photo = renditionToSatisfy.photo
                            if photo then

                                    local titleValue = photo:getFormattedMetadata("title")
                                    logger:info("Title for photo " .. tostring(renditionToSatisfy.destinationPath) .. ": " .. tostring(titleValue)) 
                    
                                    if titleValue and titleValue ~= "" then
                                        local status = photo.catalog:withWriteAccessDo( "Set 'Copyright'", function()
                                            photo:setRawMetadata("headline", titleValue)
                                            logger:info("Updated Headline to: " .. titleValue)
                                        end, { timeout=50 } )
                                        logger:info('Headline = ' .. photo:getFormattedMetadata("headline"))

                                        renditionToSatisfy:renditionIsDone(true,"")
                                    else
                                        logger:warn("No titleValue found for photo " .. tostring(renditionToSatisfy.destinationPath))
                                    end

                            else
                                logger:warn("No catalog photo found for exported rendition: " .. tostring(renditionToSatisfy.destinationPath))
                            end
                        end)
                    end


                logger:info("Processing Complete. Headline has been updated with the titleValue field where applicable.")
            end)
        
            -- If an error occurred in the pcall, log it
            if success then
            else
                logger:error("Error in post-process action: " .. tostring(err))
            end

    end
    ,
}