Just to follow up on this post with the final solution. John was correct, this was not an issue with the Redirection plugin. This issue was caused by my host (Flywheel) stripping just “utm_” tags from redirected URLs. Here’s their response related to this issue:
“By default, all UTM codes on Flywheel using the CDN powered by Fastly are stripped in order to ensure a cachable hit on the site. This was set up primarily to avoid mass uncached hits to a site from ads or social media campaigns that set unique IDs.”
I’ve also seen mention of something similar happening on GoDaddy’s managed WordPress sites.
Flywheel disabled the Fastly CDN and that solved my issue.
