OS X OpenCL ImageArray size inconsistency

The following line of kernel code yields different results on different devices with identical input:

int num = (int)get_image_array_size(regions);

On 2.8 GHz Intel Core i7 the result is the array size
On NVIDIA GeForce GT 750M 2048 MB the result is one of the image dimensions

Operating system OS X 10.12.4 (16E195)
MacBook Pro (Retina, 15-inch, Mid 2014)
Additional GPU: Intel Iris Pro 1536 MB (Has its own OpenCL issues)

Has anyone else encountered this issue?