I have posts with groups of text fields. Those fields need to hold HTML. When I eter it manually it works fine. When I import using the WP All Import added made by MteaBox (NOT the one from WPAI) the html AND the content between tags gets stripped.
The plugin WP All Import - Meta Box Integration is still in the development phase and not release yet. So we won't support this plugin in this forum. If you experience any issues with this plugin, feel free to open a new issue here https://github.com/wpmetabox/mb-wpai
Totally, the integration is released and maintained by the WP All Import dev team so I recommend using the plugin on their side to get further support.