2 observations with fixed routes.

[Fxwheels]

Interesting discussion. May or my not be relevant.

I had a circular trip created from a track. (From finish to start) I was following this clockwise. At around a quarter of the way round ( so 3 o'clock if you imagine the loop)I restarted the route. And choose CEP.

Instead of sending me in the expected direction of South ( towards6 o'clock) , it tried to route be west (towards 9 o'clock) to pick up the track.

I reported to Garmin. They had no explanation of why this is.

I can see 2 two things: you were closer the 9 o'clock than to 3, or maybe you had a route point at 9 and CEP was set to it.
CEP is not predictable.

[danham]

Something that is an interesting behaviour that I haven't seen anyone complain about yet.

If following an elongated 'circular' tracktrip ie a long narrow oval, and you wander off route to the middle of the oval, at some point you may become closer to the other side of the oval. The tracktrip will plot a route to the closest point and it will discard the original up to that point. This is most likely to happen when setting off on a route and it will make your entire day out rather shorter than you anticipated.

I think this is exactly what happened to me this week in the West Virginia mountains. It was not a track trip, but was a "fixed" pre-planned route. Per my other post about the bogus road closure warning, I think this may explain the inconsistent behavior when answering Yes versus No to a recalc request. Say Yes and it may do this if the sides of the loop "tempt" the XT to go for it and shorten your day. Say No and you get to manually pick where to rejoin the purple stripe.

-dan

[Peobody]

It was not a track trip, but was a "fixed" pre-planned route. Per my other post about the bogus road closure warning, I think this may explain the inconsistent behavior when answering Yes versus No to a recalc request.

This would only happen if there are no route points along the part of the pre-planned route that it cuts off.

Trying to out-think what the XT will do when it calculates is the most difficult part of route planning (key word here is "trying").