I understand that concept but since the vast majority of the mounts I use are flat or almost so, there won't be enough water standing to make much difference. Many of my plants are mounted on the chemically-cured epoxy side, and there is not a bit of moisture penetrating this epoxy. The roots don't seem to mind a bit. I assume you have seen the dozen or more mounted plants showing extensive roots, that I have recently posted.
I love that cork raft, though I would call this a cork log. This form of cork is sold as a "tube". I use nothing like this for mounting. What you have done is far more similar to a basket than to a cork mount. I can certainly see where you would have moisture held in/on this raft far longer than I would have on any of my mounts.
