This happens if you have a table object, saved with a post-GDPR CU (Like NAV2018 CU6), imported that object into a pre-GDPR NAV and then try to export it to TXT from that version. Post-GDPR objects include the DataClassification properties
Make sense? Post-GDPR objects are not compatible with Pre-GDPR NAV CUs.
The solution, do not mix your development environment. Currently, that means that CU2 is the preferred CU for NAV2018 development.
(The quick fix, is the remove the fields, and RETYPE them (Cut’n’Paste will not work).
I’ve seen a couple of explanations about this, but they seemed incomplete, so I did this quick write-up.
This is part of a very old C/Side bug, (or feature might some people from Microsoft argue) where unknown properties are carried along behind the scenes when importing FOB files.