CRM Copy Transactions and Products Custom Fields Values to Issue
Post-function copies Transactions and Products&Services fields from linked issues of chosen link type while transition.
Add post-function to transition you need:

Press "Add" and add parameters to post-function.

Parameter  | Description  | 
|---|---|
Source  | Choose Issues field to copy Transactions and Products from. Parent issue, Linked issue and Issue Picker field are available.  | 
Link Type  | Select link type for Linked Issue source to copy Transactions and Products from.  |