An update! A month and a half later I decided to try one, to see if it was any better. The sourness is gone! Hurray! 3 months of cool weather seemed to have fixed it.
The Westvleteren is batting at about 80% of what it had been; aroma is there, but the flavor doesn't have the strength it did, nor the finish. Still a wonderful tasting ale however.
Thank you all again for the responses.