Exporting videos with coordinates

Hello hello!

I am going through a major exercise of GPSing all of my photo and video library. Before smartphones (... yes, i'm old) and with older models, photos would come without coordinates.

here is the issue:

- if i upload in Lightroom cc a video taken with a smartphone and recorded with coordinates, it imports the video with coordinates. And if i export it again, coordinates follow, and it's all good.

- if i upload a video without coordinates, i add them in LCC, i see them in LCC. But when i export the video the resulting file does not have coordinates.

I've googled and tried everything i can think of. Is it me?

with thanks,

g