There is a known issue where task plans are not included as part of the change model UNL neither using the Script Utility nor Export/Unload option (“Use Data Map”).
There is an ER already opened for this(QCCR1E127787), link below:
According to CPE, “since task is not in same file as change model unload does not contain it, customer can export related task by themselves to work around it”
However, it does not give much detail on where are stored those tasks so it can be confusing.
The records displayed in the component are saved into that table under the file name "ChangeModel". In other words, you should add an unl of the “changePlan” record to export the whole configuration (ChangeModel and Tasks).
-Jose Pablo Mora-