Samyang 8 mm

Need a bit of help from the brain trust here.

My Samyang 8 mm works well with my X-E1.  It doesn't work with the XPro1.  For some reason the shutter won't trip with the XPro 1.  Yet the XPro1 works with any of my other lenses.

What setting in firmware am I missing here?

Perry

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X100; WCL-100
XPro1; 60mm Macro, 35mm f1.4
XE1; 18-55 Zoom, Samyang 8 mm