Why does my Dezl 770 drop arrival time while in route?

Disregard. I misunderstood "loses arrival time."

Make sure that you set the non navigating choice to current time. Set the Navigating choice to ETA.

Has the unit stopped navigating when the Direction pops up? If so, that is the problem to check on, why has Navigation stopped?

These blacks change function according to whether you are navigating or not.

Blocks, dammit, Blocks!!!!!

arrival time just switches to direction of travel. If I press stop and set destination again arrival time shows up again.

Next time, don't cancel the Navigation, just click the direction Block and choose ETA.

why this happens in the first place.

Are you using Track Up or North Up to view the map?

On my DS55 and my 3597, ETA can't be seen unless you select it, while navigating. I don't know what the default is. I wouldn't care to do a hard reset to see.

I don't know that this applies, but I vaguely remember reading here years ago about compass headings appearing to a user—and it was found that it appeared only when the GPS was set to North Up rather than the more common Track Up. It'd be a quick test on the Dezl if it was set to North Up to switch and see if ETA remains when using Track Up. My guess is that the odds of success are under 40% for Frside007 but what the heck? What else could people find to do today, watch a football game?

and always have.

If I set a route I can press on the window where arrival time shows in lower right corner and have several options to choose from. I have arrival time selected but you can select time till arrival among others. Was wondering if it has to do with # of satellites garmin is tracking or if signal weakens but but enough to give the lost satellites signal. Hmmmm

That setting is for instances of multiple destinations.. the arrival time at the last stop.. or the next one.
I notice the estimated time of arrival frequently gets lower as one gets more or less red lights (or drives faster or lower) on the journey. Not sure it that is what the OP is concerned about.

This happens (losing arrival time and switching to direction of travel) when going from present destination to next one. Losing arrival time happens while on the Interstate going posted speed limit (60mph) or in town with multiple stops at intersections. Doesn't happen often. Less than 10% of my destinations. Maybe it has something to do with time/distance from present location? One of my stops is approx 50 miles from my start location using multiple highways/freeways. This is one of the routes it happens on the most. I am following the route the Dezl770 selected when it happens.

To put this in a nutshell, the function of the lower right hand window should only change when you start a route.

When not navigation, whatever function you have chosen will ALWAYS appear. I have Current Time Set.

When navigating, whatever function you have set will ALWAYS appear. I have Arrival Time set.

They should never change on their own. If they are changing, then there is a problem. The first thing you need do is turn the unit off by holding the Power Off Button until the unit restarts.

Go to the Map, press the lower right window and set the Function you wish to display while NOT Navigating. Then, create a route and start Navigation. Press the lower right window and select the Function you wish to always see when Navigating.

If what you have set in the lower right window ever changes on it's own, it's broke. It should never change without User Intervention, with the exception of changing from Navigation to Not Navigating.