I’ve found a conflict with Woocommerce and SG Optimizer. When SG Optimizer is turned on, my Thank You emails are not displaying the download link for downloadable products. If I turn the plug in off, the emails display correctly. After a lot of fiddling with settings, turning off just Memcached seemed to do the trick.
Please could you look in to providing a fix in a future release?
Thanks for reporting this. I am afraid that at this point there isn’t much we can do to fix this so please, keep Memcached off. We have a task about reworking the dropin we use to enable persistent caching for WordPress which should fix this problem but unfortunatelly, I don’t have an ETA when we’re going to release it.