Thank you for the quick reply.
I was encourage by the ease of implementing your idea, and my hopes were high. Alas, it does not seem to be correcting the issues.
I tried doing this and waiting quite a bit of time for the cache to update, but I continued to get the same errors in AMP test.
I then re-activated W3 Total Cache in the AMP suppression settings and tried the AMP testing again, but I am getting the same result.
Note that with each change I am emptying all caches.