Waypoint time calculation runs backward in time (both on the ground and in flight). The only way to restore correct operation is to keep a TIME page open.
Version 1.1.5
This happens to me if I already have a flight plan with the same origin & destination in the WASM folder WASM\MSFS2024\inibuilds-aircraft-a350\work\flightplans. Just delete them and it works.