When navigating a course the est time and arrival are computed wrong

I am using Explore with an Inreach Mini 2 for cycling. When I set a course in the app and then start navigation, the app computes Est Time remaining and Arrival time that are too long and appear more correct for walking.

Eg I started a 33km ride at 3pm - by 4pm I had ridden 8km and stopped to buy food so had 25km remaining which even conservatively should have had a time remaining approx 3h however the app was estimating SIX HOURS remaining  and arrival time of 10pm

This kind of thing is happening every time I use course navigation - the duration is always too long and arrival time too late. Sometimes by a lot