2 questions:
1. I upgraded a yellow (lengendary) armor, it turn out the defense droped by 1. wtf. Is it just like upgrading a unique item in D2, such that the defense could possibly drop?

2. I upgraded some green and blue items. wtf, and I found some of the mods on it got lost during upgrade. For example the boots originally had like +11 defense to all special attack, and after upgrade, that thing is gone from the boots. WTF. I wasn't looking and just blindly upgraded the boots like 3 levels, and the boots became a plain white boots. LMAO. Could you guys give me a hint? Thanks.

this is all news to me alot is still unknown in the game

upgrading increases item level, which should increase the defence, since defense is based on item level
no idea why it would be different

Strange

I've upgraded lots of shit and rolled extra mods on many whites and greens and blues and never lost a mod

alright thanks guys. I don't know, but I am playing on single user mode. not sure if that makes a difference...

You need the latest patch.

Upgrading legendaries is still bugged, but not always. This has been happening since beta, and is getting better each patch.

Plus, like duped said, make sure you are running the most recent patch.

Thank you!!

You're welcome.

rotfl.I was scared lol something shit like this could happen.