Pretty sure this report isn't accurate. A lot of add-ons get exported and even we regularly export add-on data ourselves for XF and our add-ons.
We would have come across this ourselves and had many reports of it otherwise.
Can you please reconfirm the issue and verify the reproduction steps?
To be clear, add-on data is exported from the contents of the database (so, not the file system contents) and templates specifically are only included if they are assigned to the add-on and in the master style (style_id 0 only).