When using the Rapid Fire skill, I noticed that if you were to use a non-energy spending attack, (In my case it was the seeking arrow that I was using) the character would play the ‘Rapid Fire’ animation again, though it would fire no arrows.
In summary, Rapid Fire → Seeker Arrow (spamming left click for the soonest possible seeker arrow) results in a “dry fire” animation of Rapid Fire to play again, which is a very long animation in terms of Diablo, leaving the player vulnerable and not outputting any damage.
Edit: When attempting to recreate the issue just now, I could not see the issue still occurring; this may have now been solved.
I also experienced this bug many times the last 2 days but wasn’t sure what was triggering it. Something about high APM alternating left and right clicks causes the rapid fire animation to “dry fire” - the animation and even the sound plays but there are no projectiles being fired. I was using Forceful Arrow as my left click (the one that does is not homing, every 3rd shot makes enemies vulnerable).
This is still happening to me all the time. Mostly when I use Rapid Fire and then try to move in any direction, the character just wants to fake-rapid fire again and I inevitably get hit by whatever I’m trying to avoid.
Would hope this is fixed before launch. 
Really ruins the ability.
Yup still an issue. I posted about it too, hopefully gets fixed…
There seem to be a lot of issues still on the table skimming through the bug report page.
OP’s initial report was using a basic skill but it’s caused by spam click to move right after you shoot 1 rapid fire