I heard back from Cakewalk approximately a day after I submitted this thread and we tested a few things. They said they weren't able to replicate my error. Unfortunately, I've been traveling off and on for the last couple weeks, so this is the first chance I've had to test their suggestions and get back to them.
However, in my working with the OP-X developer, we came up with a fairly simple workaround. I could just hit the "copy" button at the top of the VST and copy the current patch/settings into Program #1. It always seems to revert back to Program #1 when Sonar reloads, so this ensures that the sound I wants loads properly. Fortunately, this "copy" function is instance specific, so it doesn't modify the default program list in any way.
I wanted to pass this along for anyone else experiencing the same problem with this particular VST.