Please use Company-managed projects as Lookup project
Try to add context to the custom field instead of defining multiple fields with the same name to avoid naming conflicts
If you are executing the Lookup post function when the issue is being created, please place the post function after Creates the issue originally.
The post function runs asynchronously. So do not add another post function that relies on the output of the Lookup post function (e.g. copy custom field value) within the same workflow transition. You can add another lookup post function to populate the value directly instead.
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