One possible reason is that in my case the sync (#3) that is failing has thousands of nested sub directories with lots of content in each. If it is doing a read of each directory first, it could be maxing out the API connection limit and preventing uploading.
I think this might be the reason although i'm not sure why sync from Gdrive A to Gdrive B does not have this problem.
Does sync have parameters to avoid getting API bans from dir scanning @ncw whereas Move or Copy do not?
I get banned when doing Move from server > Gdrive yet no bans from Sync Gdrive A to Gdrive B.
@rooker156 what is your command that gets you banned?
Tried deleting the empty dirs in my upload folder - got banned after ~60GB upload, compared to ~600GB the day before.