Sharepoint Workflow task with title (external participant)

Question

Hi all

I made a custom sharepoint workflow with Visual studio, the workflow starts when a new item is inserted in a list

I assigned the title of the task to reference a field in the new item

TaskProps.Title = "Please prepare Hardware for project " + workflowProperties.Item["Contract"].ToString().Split('#')[1];

the task title is correct but i find the string (exteranl participant) concatenated the title of the task

what can be the reason for this ?

thanks