Can't post an item on the TP
I have read several times on this forum that upgrading an item with runes or jewels will cause such a result.
Don’t know though if it is a bug or intended.
Upgrading an item, i.e. applying an upgrade to it, will make it soulbound to you immediately.
When you attempt to apply an upgrade to an item you should be getting a popup confirmation that warns you that it will become soulbound to YOU (first line), as well as destroying any existing upgrade on the item (last line).
It’s likely you just missed/skipped the text in the popup. If you’re not getting that popup on trying to upgrade any future items, you might have an unusual bug to report.
Yea, I completely ignored the pop-up.
It seems the bug then is that the tooltip doesn’t update to show that it has become soulbound to me.
The item is actually “souldbound at use” AND “souldbound” at the same time. But only one of those attributes will show up, so you will not see the “souldbound” as long as “soulbound on use” is still active.
Using the item will remove “soulbound on use” and “souldbound” will show up.