My response assumes you have the most recent updates on the HD500 and at least 1.82 on the JTV...
The unit remembers the state you save the patch on the HD500 -- with the mags on, and saved that way, it will come back with the mags on when you hit the footswitch. If you saved the patch with the models on, it will recall the patch with the model on. Either way, to fix that bit, you just save your patch with the JTV mags on if that's how you want it. On the second one, I have several patches with the HD500 forcing a model and specific tuning, set up on the HD500 Edit page that shows the mixer, I believe (don't have it in front of me at the moment). I have not noticed a change of behaviour since I updated to 2.10 on the HD500 or with JTV version 1.9.
Ok, so I do have all the updates, including the JTV updates to the most current (as of a week ago, haven't checked this week yet).
Anyways, so when I used the "save" on the HD500 (and not in the software) after "turning off" the JTV Variax (so it was on Mags), that did save as you suggested.
Now, I need to check on the tuning issue.
Strange, though, that I can't "save JTV state" from within Edit instead of using the HD500. But, if that's a glitch, I can live with that.
Not sure I fully understand your problem, but when you say "save your JTV state" when in HD Edit be sure you do a "Send" to download your revised patch or setting to the HD 500 hardware. Making a change in HD Edit doesn't save it on the HD 500. All your JTV settings can be saved in the patch on the HD 500.
I have noticed this as well with just a single patch. My band covers Quiet Riot Metal Health. This requires me to use the Lester Model 1, and 1/2 step down tuning.
The first way I tried this was manually selecting the lester model 1 and changing the tuning to Eb, etc. I did this within POD Edit software. However when I did, the model selector on my JTV-69 was not lit up. I saved the preset, and then clicked Send Selected from the top of the Edit window. However upon recalling the patch, there was no change. Recalling the saved patch showed the variax in lester 1 however tuning was standard.
However when looking at the POD display, I can see the patch is set correctly, so I save it, and when I select 3C, it chooses he correct model and tuning.
Saving/Sending it through the POD Edit software did not do this, Manually pressing save on the POD after sending the correctly modifed settings worked.
The Second time I tried it, I set up the preset in POD Edit but I pressed the Model button, selected Lester 1, which updated on the screen, and then dialed in the 1/2 down tuning using the wheel on the variax. After doing this, I sent selected, and it was correct.
Then I tried unplugging the VDI cable from the POD to the JTV, set the preset by hand using POD Edit, and then sent selected and it stuck.
So my experience is, if the Variax is plugged in, and you do not manually select the model and tuning, while setting up the preset, it does not stick, however when you do, it sticks and is updated on the POD correctly using POD Edit.
If the variax is unplugged, and you set the model/tuning using POD Edit, it sticks.
Perhaps there is some disconnect when the variax is plugged in. I am not sure. Maybe this will help you in troubleshooting.
Either way, I love my POD/Variax JTV-69. It is the best thing I have used Live. No switching guitars, no need for acoustic guitar standing by. I use Variax > VDI > POD to front of house, and have nothing but good experiences.
The DT-50 head will be my next step, after I get the $$ together.
Ok, so I think you found the issue - not sure how to raise this to Line 6 - but it appears you are right. When the guitar is plugged in...issues. When not, it saves right. Weird - likely some bug somewhere.
I have the DT-50 head. I'll tell you it's a great amp. Might want to change the tubes, but otherwise great.
I would recommend a THD Hot Plate or similar. That lets you crank the tubes while mellow on the volume!