The batteries are definitely causing the issue.
My installer says there will be a filter capable of handing the amps the batteries put out next year that would be for consumers. Right now there are commercial grade filters capable of it but they are overkill and too expensive. $2000. My installer also suggested I try Clip-on Ferrite Ring Core RFI EMI Noise Suppressors on the circuits having issues as a temporary fix. I purchased these and installed them today. https://www.amazon.com/dp/B08BPHCXR3?ref=ppx_yo2ov_dt_b_fed_asin_title
I tried them on the problem circuits and even on the lines coming from the batteries themselves. It may have made things slightly better but definitely not acceptable. They make a pretty loud buzzing noise or humming noise too.
Since I really only have 4 to 5 Insteon switches that are exhibiting issues out of probably 30 or more I am planning to switch those with some of my other Z-wave switches and see if I can get all issues taken care of. That's my new plan anyway, until there is an affordable solution.
Sorry I don't have better news.