Extremely puzzling volume velocity values on re-sim of the same pyro .hip file

[smbell]

Sorry for the long post, but I've run into an issue that is driving me crazy and I can't seem to figure it out.

I have a pretty simple pyro sim with some Disturbance and Turbulence using Pressure as a control field. I ran the sim Tuesday night, and in the morning I realized I went a bit too far in both.

Fast forward to today, when I had some time to re-run the sim. I opened the original file, adjusted both the Disturbance and Turbulence down a bit and rendered out my file cache.

I immediately noticed that my files were more than 2x the size. Same voxel size, same channels etc. Upon viewing the velocity channels in the volume visualizer, I can see that the new sim has velocity in all the voxels, where my original sim has it only near the actual smoke and all the values are zero outside this area.

Now where it gets stranger is that I re-opened the original file that I used to cache out the original sim and re-cached a few frames and it now looks like the new sim... I'm usually all for chalking this kinda stuff up to human error, but I'm 100% sure it's the original settings and file and everything.

Is there anything that anyone can think of that would cause this? I really would like the original velocity behavior back since it has much smaller files, uses less memory etc. it's killing me here.

I've attached a pic of the old vs new sim with the same settings, and a later frame where you can really see how it looked on the first run.

[smbell]

I'm a dingus. Somehow sparse solving got turned off.