Problem with Click box "Disable click Sound" setting

I have created a project in Captivate 9. It has approx. 350 slides. I have captured 7 simulations and merged them in 1 file. After publishing the project I noticed that the click sound of the click box is not audible on some slides. I have unchecked the “Disable Click Sound” dialogue box for each slide. Still, the click sound does not appear for some slides. Moreover, the behaviour is not consistent. Sometimes, the click sound for an element in a simulation screen works, and sometimes it does not work for the same element on the same screen. The output is HTML5 and we are viewing it in Internet Explorer 11.