Phone calls stopped after first call: Samsung Galaxy S4

Today, I had 5 meetings at work.  I normally use my work issued Samsung Galaxy S4 and my Plantronics bluetooth headset with all my conference calls.  This has worked great for the past couple of years but today I noticed that after my first call, I when I dialed my next call, I did not hear the conference call lady ask me for my conference code.  This seemed strange.  I called my wifes phone but did not hear any ringing on my end.  My wife stopped in my office awhile later and said she saw I called.

I rebooted my cell phone (power off then physically powered it on, never trusted reboot but on the S4 it appears reboot does the same thing) and I was able to connect to my next call using my bluetooth headset.  I thought problem solved!  Nope.  The next call same symptoms, no ring or conference call-in lady's voice.  I suspect if I called my wife she would answer and not hear me.  Again, a reboot of the phone fixed the problem.

I did some experimenting and discovered that as long as I did not use the bluetooth headset, my calls would work.  Once I used the bluetooth headset for a call, that disabled my voice and microphone from the bluetooth headset AND from my phone (I disconnected the headset and still had the same problem).

Removing the battery, SIM card and SD card and replacing them did not solve the problem.  Calls worked fine until I connected the bluetooth headset and made a call. After that, any call, with or without the headset failed.

Googling for answers showed some promise.  One solution was to TURN OFF Google Drive.  I did that and even rebooted the phone. Same problem.

The solution?  Turn off the "OK Google" feature.  I recall that over the weekend, I disabled Google Now function and I think I enabled "OK Google" on all pages.  There was a reference to "OK, Google" causing this problem when I was Googling.  I had to reboot the phone for the "OK, Google" to be disabled and to be able to make calls with the bluetooth headset.

I'll probably keep "OK, Google" disabled just like I disabled "Google Now".  They are neat features but I don't really use them all that much.