Seems this is an old issue not fixed.
Forced to reopen the text messages on FR 965 list to delete the last one left, workaround is start delete from bottom list but when there are several messages this is uncomfortable.
Garmin local support says that this is a problem with message feature/setting on iphone (XR iPhone).
Anybody with same problem using Android/other iphone ? Just to understand where is the issue (iphone/FR965 sw).