Really gone down the "Rabbit Hole" with this recently, and trying to do lots of little tests, plan to start messing with the TripManager tool, still pissed of that it is needed due to a "bug" Garmin will not fix (Repeated U-Turns or "RUT" bug) and claim is "by design", however the workarounds are out there.
I think the best fix has been documented in several topics, which is to ensure the route is a "saved" and not imported route, I believe XT2/3 you can just "Duplicate" and imported route and that will not have the issue, for my XT I have to start the route, then come out of navigation (but not cancel) and then "save active route", then stop navigation, then start it again using the "saved" route.
Lots of info here:
Remember the Repeated U Turn (RUT) behaviour, which crops up if you skip a route point early in a route and then later deviate from the plotted route ? What…
zumouserforums.co.uk
Worth a read throug, but if you cannot be bothered...
Basically it behaves differently with an "imported" route, something I was not aware of was that the route is not purely calculated by figuring out how to get from one way-point (shape or via) to the next by the device, but a certain amount of other data related to the exact route is in the GPX file - I (wrongly) assumed this was not the case and every route is "calculated" when imported or started.
The "Bug" (or feature according to Garmin) is as the route was not originally calculated by their software then it should not be changed on the fly, so if you miss a point (even a "shaping point") it will always want to go back to it, unless you ride until you pickup the original route (although I have seen this fail) - so even if you hit the "Skip Waypoint" button it wants to go back to the point you "skipped" - so if by design then Garmin should remove / disable the skip button for "imported" routes and warn you when you go to start them.
The fix I had been using was to stop navigation when it went mad, and restart the route with using "next closest entry point" which mostly worked well.
Some dude has put together what looks like a really neat app that can fix routes in bulk
For a big trip this would help me a lot, I can dump all my routes onto the device up front, then get this app to remove the flag that it is imported which saves a load of pissing about....
...but puts me back into the dark ages (almost) of having to do all my planning and load every route that I might use from the PC to the device and then fix them with this tool....
...Although I can still send a route from MRA and use the start / save / stop / start again trick....
...Considering this is all due to a single bit in the file they set to a "1" that is changed to a "0" solves the U-Turn issue it is absolutely bonkers Garmin never either abandoned this flag as I cannot see it ever does anything good, or gave an option to remove the setting when imprting / starting / recalculating a route.....
...I can imagine all of the support team and programmers al knowing this is the only sensible thing to do but some fuckwit manager not wanting to admit there was ever an issue, so everyone has to put up with this issue, get lost, frustrated, hate Garmin just so he can insis he is right, meanwhile loyal customers abandon their products at an exponentional rate.
Great work from the community who it seems identfied the bahaviour, proved the behaviour and eventually decoded a load of Garmin files without any help from Garmin on the file format, found what caused the bug, reported the bug and still got a big "fuck you" from Garmin.
Someone should be sacked, however hopefully the info gets out there to as many pissed off XT users as possible.....
...I would still never buy a new XT2/3 on principle, but as used ones pile up as people walk away I might buy a used one if they get cheap enough.