Selecting an enemy
It could be that you were fighting someone with taunt which forces you to change targets and attack. It could also be that if you double left click on the screen where no one is you deselect your target. I haven’t noticed that happening before so I can’t say if it’s a glitch or not.
couple of things to check:
in the options make sure you have autoattack on. this will select your target for you when you use a skill.
also, try to stop using the mouse to interact. go into the options and set keys for “Target Nearest” I use “C” myself. it’s close and easy to reach, and you can always tab target to the next one if you need to.
The mouse is a horrible thing to use in combat.
Another trick is to hit CTRL-T when you have a target you want to keep. If you mouse-move you are inevitably going to deselect your target. If you’ve CTRL-T’d it, not only do you get a big red target symbol over its head, but a quick tap of T reacquires it as a target. Anyone in a party can set a target at any time and everyone else can just tap T to get it. (Or can CTRL-T something else to move the target symbol, so you can get some tug of wars going on that).
Keep in mind that an enemy entering stealth will lose all targeting on an enemy.
Per above, it is a very GOOD idea to stop using your mouse as a target selector and start using the target selection buttons you can set up in a variety of ways (including CALLING a target that your party can then easily target also, or targeting an enemy that one of your allies have CALLED as a target).
Also, the suggestion to enable AUTO TARGETING has both advantages and disadvantages and I doubt that many PvP players would suggest using it (but it’s 100% YOUR call). Blowing your best skill on the wrong target due to the game selecting wrong, is NOT a good thing.
Fate is just the weight of circumstances
That’s the way that lady luck dances
Thank you all, I haven’t had an issue in a while, I don’t use the mouse to select target I press tab, but luckily for me I have not had an issue in a while. I will keep all of this in mind if it arise again.