Magento – Source fields are not mapped. Document: catalog_eav_attribute. Fields: layered_navigation_canonical

When migrating a Magento 1 site to Magento 2, I hit the following error;

100% [============================] Remaining Time: < 1 sec
[2019-01-21 11:19:03][ERROR]: Source fields are not mapped. Document: catalog_eav_attribute. Fields: layered_navigation_canonical

Adding an ignore tag in map.xml didn’t fix the issue, as it needs to be read at the EAV step.

Change map-eav.xml.dist to
map-eav.xml

Add an <ignore> tag

Within <field_rules><source>

<ignore<field>catalog_eav_attribute.layered_navigation_canonical</field></ignore>

Finally make sure the you also rename the etc/opensource-to-opensource/map-eav.xml path in config.xml