I can guarantee it is not solely modded stacks. Wife has the bug, she never plays online with anyone else. I dont play terraria online with anyone else. She had zero modded stacks in her inventory. Her data size was leas than 15mb, same as mine. I was able to okay no issue. We ended up deleting all her old saves, going back to the 360 and she can play. I had saves going back that far too and had no issue.@Unit One It probably is the modded stacks I only have one that was dropped for me yesterday of 25000 healing potions. My other account is pre 1.3 as well and I was able to log in on there just fine. Although I did not have any worlds that where pre 1.3 on that account.
I just hope they figure it out.