Resolve Error the given key was not present in the dictionary plugin error

this error is due to no fields are not getting then create a Post image inside Update step




Now add this Entity Alias StudentCourse in your plugin where your write "Target"
For example:

 if (context.PostEntityImages.Contains("StudentCourse") && context.PostEntityImages["StudentCourse"] is Entity)
            {
Entity entity = (Entity)context.PostEntityImages["StudentCourse"];
}