When using the new workflow it assumes that ALL of the original tags are intact. It is likely that Lightroom, or any other image management software, might not be writing all the tags that are needed. The new workflow looks at some of the DJI specific XMP in an attempt to estimate GSD and footprint size. If that isn't there it could be causing what you are seeing.
From the Data Collection guidelines that are agreed to at the time of upload:
"EXIF Tags Intact - EXIF tags should not be modifed by 3rd party image processing software. We need all the of the tags the camera originally places in the image files. Photoshop, Photos, Photo Manager and lots of other softwares have been known to corrupt the tags."
The new DJI specific workflow relies on a few DJI placed tags that are not checked in the Classic workflow. This is why they will still work with the old version.