@tom-carter-0
Update: I switched back to my Garmin 595 for a trip I just took. Still using the Shoei Neotec 2 Sena 10U. I had the same word cutoff problem with it. The only difference was that occasionally it would work fine and not cut off the first word or two.
Therefore, it appears to be a Sena issue, not MRA Nav.
I had a previous version of the 10U for my Neotec 1 helmet using the same 595 without issues – so it may only be an issue only with the newer Sena version.
Sena suggested re-pairing – I don’t have a lot of confidence that will work but you never know…just like re-booting your computer, sometimes that works on a lot of issues.