Hmm... further weirdness, but, first, thanks to everyone for their replies. Sorry I haven't posted in a few days.
Maybe the project I've been working on is corrupt. I can't reproduce the issue in a new, empty project. That said, I can't reproduce the original issue in the project I've been working on either. I have, however, been experiencing other issues with the TS-64 in that project. The first time I tried to load it today, I was unable to pull up the manual entry box by double-clicking on any of the parameters values and, after clicking on the attack value a couple times, Sonar crashed. Sonar hasn't crashed again since I relaunched, but I've still been unable to get to the manual entry box for any of the parameters.
Besides the project potentially being corrupt, it makes me think that perhaps the TS-64 isn't the most solid plugin. Although I'm unable to reproduce it currently, this isn't the first project in which I've experienced that original issue of the values resetting. For the time being, I'm using the transient effect in Alloy. It has fewer parameters, but isn't doing anything unexpected.
Thanks again for everyone's input!