When you mount up, the cast doesn't actually finish till a second after you're on your mount, so if you move, it cancels the cast.
When casting kolto infusion on an IA operative, if your tactical advantage runs out after you've started the cast, then it cancels the cast.
The IA operative acid blace tooltip is still incorrect.
A few quests have invisible dialogue choices, I don't know if this is an issue with the quest itself, or the UI
Casting bars sometimes cancel for no reason, even though the cast is still going through.
If a channeled cast is interrupted, the bar doesn't go away.
Companions get stuck for no reason at all, a lot.
Things bought with badges/credits can't be sold back for their original amount in a limited amount of time.
Some of the PVP daily quest don't always work on the first time.
Ill post again if I find/think of more.