Shutter fires twice in single mode?

[ron777]

My a7rIII, on occasion, behaves in an odd fashion.  I was out shooting yesterday, and with the camera in single shot drive mode, a solitary press of the shutter release resulted in the sound of the shutter firing twice in rapid succession.  This has happened before, but it is entirely intermittent and unpredictable.  Operationally, it does not interfere with the shooting process, but it is a strange occurrence and I wonder if others have had a similar experience?

[LiveShots]

Front shutter curtain may be enabled, or you're pressing the shutter twice, which can happen inadvertently if you get the right amount of depression.

[ron777]

I'm fairly certain that front curtain shutter is off, but I will check just the same.  But if that were the problem, would it not occur all of the time?

I guess that shutter pressure might be a more likely explanation, since I have the default, focus with shutter engaged after finding back button focus to be a bit of a hit and miss scenario for me (meaning, I often inadvertently pressed the wrong button).

Thanks for your input