I am having the same problem. I have tried using a different browser, and listing on MOnday, rather than Sunday, since Auctiva seems to have "sunday-itis". I'm still having the same problem. just to be clear.
I am ending my GTC items on EBAY. Bulk re-listing them thru Auctiva, selecting 30 day on all, individually, and 3-% of them are still coming thru re-listed as GTC. I'm wasting my $$ ending and relisting these continuously.
Please help. I have reported it, and have gotten no response