Anyone else experiencing this?
 
When I save my project, my TL64_TubeLeveler_64 "Drive" and "Output Gain" levels mysteriously change all on their own.  So I have to reset them, and remember to reset them when I reopen the project.
 
I'm using the "Mix Warmer" preset and there are no stray envelopes here.  I even created an envelope for the "Drive" level hoping that it would nail down the level when I saved, but nope, when I saved even the envelope moved!
 
More Info...
The Track is using only two envelopes, Gain & Volume
The Track has the following plug-ins in use (in order): 1) LP64_Multiband_64, 2)Sonitus: fx Compressor, 3)TL64_TubeLeveler_64

Nope, just tried it in a project, and I duplicated your Fx chain and the TL64 retains all parameter settings.

I'd try just re-installing that one plugin.

It does seem to be something in the TL64_TubeLeveler_64 plug-in because after reading your post (thanks!)...

I tried to save the settings within the plug-in as a preset by changing the name in the Presets box and hitting the save icon.  The "Drive" and "Output Gain" levels changed back to what appears to be some preset values everytime I saved.

Then I used the Preset Options menu "Save Preset" Command and saved as a *.fxp file.  Then (from the Preset Options menu) used the "Load Preset" command to load that file and now the "Drive" and "Output Gains" stay locked.

Kind of weird, I'll look into reinstalling the plug-in and see if that fixes it.  When I get to that I'll repost.  Again thanks for your post Bristol_Jonesey.