If you switch back to an old strap, does it still happen? Ever have issues while doing other things?
Nerves can be complex and anatomy is not always typical. Carpal tunnel can result in symptoms going all the way up the arm, but more typical if it has been going on for a while and the median nerve is inflamed. Carpal tunnel also sometimes involves the ulnar nerve distribution.
Could be a combination of carpal and ulnar tunnel brought on by compression and your wrist anatomy. I had carpal tunnel symptoms going back to childhood, finally got it fixed 2 years ago. Still have occasional ulnar nerve symptoms most likely related to cubital tunnel syndrome which is a more complicated fix than carpal tunnel. I'm still rather young (38).
Could be a brachial plexus issue, but that doesn't map cleanly on to what you described. Nor does a spinal nerve root issues map well to what you described. However, nervous and anatomy are more complex than a text book and speaking with an orthopedists who specializes in hands is the answer if this is problematic for your life (or if you start having muscular weakness in your hand).
You can try provoking maneuvers which can help (carpal tunnel compression/percussion, Phalen test, Tinel's sign, elbow flexion test, Etc) which might help localize the problem. While many of the tests are simple, having some to help make sure you are doing them correctly and help interpret the results helps. I'm a nurse practitioner and while not my area, I can consult professional references, and it has still been helpful for me to see an orthopedist for assessment and interpretation.