You mentioned that the issue happens with both PAS and the throttle, so it?s probably not the magnetic ring, but it?s worth looking at. I have over 2000 miles on my RW4 and have had to clean off the magnetic ring a couple of times.
https://support.radpowerbikes.com/Maintenance_and_troubleshooting/Throttle_and_pedal_assist/Pedal_assist_system_(PAS)_troubleshooting_guide

FYI, 22 inch tires are available here:
https://amzn.to/45yn1iK

I plan to get these to replace my Rad tires.

My original springs broke early on, but I now have 1000 miles on my RadWagon with this setup. Get some small hose clamps and attach as shown in photo.

Glad I managed to get some. Shipping cost is ridiculous!

Tubes now available! https://bit.ly/2IuFV5n

22x3 tubes now available! https://bit.ly/2IuFV5n

QuoteThanks for sharing these nice alternatives. How is the quality of the seat pads?

The quality seems good. We don't have a ton of miles on it yet, but I think it will last a long time. My passenger is quite happy and comfortable.

Also, it attaches (and detaches) easily with velcro straps that work fine with the Rad tubing.

I have found a couple of replacement tubes that are close to the correct size. Disclaimer: I have not yet ordered/tested either of these and cannot vouch for them. From what I have read you should be able to use a narrower tube in a wider tire, but it's unclear how close the tube needs to be. The max listed width for these tubes is over 1/2 inch too narrow, so I'm not sure if just adding more air to them will work or have any negative side effects. I'd be curious to hear about any other tubes that folks have found. Both sources below are for 22 x 2.1-2.4 tubes:

1. https://www.sandmbikes.com/product/hardgoods/rubber/inner-tube/
2. https://www.danscomp.com/dans-comp-deluxe-bmx-inner-tube-schrader-valve-22-x-2.12.4-32mm-446006x1x2125/p1132266?v=1080559

I didn't want to wait for running boards and the deckpad, so I ordered the Rad Power passenger pegs (in stock!) and then got the Mini Magic Carpet seatpad from Xtracycle. My son is now traveling in style and comfort on my RadWagon!

Xtracycle has two sizes of Magic Carpet:
https://www.xtracycle.com/product/mini-magiccarpet/
https://www.xtracycle.com/product/magiccarpet/

I went with the mini and it's perfect for a single passenger.

This is what I got from customer service when I asked them when replacement tubes would be available for the RadWagon 4:

QuoteThanks for reaching out regarding your wagon! We are still working on stocking spare parts for this bike, but they will be available at the link below when we do have them!

https://bit.ly/3x6Vkwg

In the meantime, you might find success at your local bike shop or with a Google search to find retailers that sell 22x3" tubes. Unfortunately, I can't give any brand names out as we have only tested the quality of the tubes that come with our bikes!

So...not super helpful.

New springs are on the way from Rad. It seems like that's their approach for now. Interestingly, they added a new help topic related to kickstand springs this week: https://radpowerbikes.zendesk.com/hc/en-us/articles/360058022653-RadWagon-4-Kickstand-Spring-Replacement-Guide

Thanks for posting this. I got my new RadWagon 4 in September and after ~40 miles of riding, I noticed that one of the kickstand springs was missing. (The kickstand was rattling around a lot going over bumps, so I took a look). The second spring was pretty well bent too and was close to failing.

I found this post with a quick search and was happy to find it! Today, I added two new springs and attached one end in the location suggested by Jason. I ended up using small hose clamps instead of wire for the attachment points. Early tests have been successful and hopefully the fix will last.

I also emailed Rad support, but it seems that they are a bit overwhelmed right now and I have not heard back yet.

Overall, I love my RadWagon, despite this annoying issue.