Mac - Seadrive - Can't "save as" on Seadrive destination

Hi,

When using “Save as” option on Firefox to direct dowload a file on a seadrive folder, the download failed, and a 0k file is create.
A few users seems to use this “save as” feature, the default in Firefox is to save in “Downloads” folder works fine. They did not notice that download failed as Firefox only show a litle red dot to notice the failure, then the file is created with 0k.

This doesn’t happen on Safari or Chrome.
Safari and Chrome use a local folder to download the file, then move it to the destination folder.