I personally would not be holding off on patching IOS when there are significant security fixes in the update as well. Triumph needs to pull their finger out and resolve their software issues. It is deplorable that they sent out a message like this.
I work in an IT computer and this new version of Apple is creating havoc... several things have changed internally and breaking apps that were working fine till the previous version... this message from triumph do not surprise me at all... saying so, connecting an iPhone to a recreational motorcycle is not end of the day... well maybe if you use it for delivery
Just had my bike in for general service (oil/filter change) and they updated with the latest firmware (dash/ecm/bluetooth). No issues with my iPhone running iOS 16.