Sometimes RWGPS seems a little glitchy. I've had it do that to me. FWIW I've often been able to fix it by hitting the "undo" button just once. It's as though RWGPS somehow thought it got input to show the next route segment and then change the color back to the color changed from. hitting undo often seems to undo that unasked for color change.

Thanks James.  I had found the Undo thing too, but (and take this with a mineload of salt because I am not clear what I actually did) it might also have messed with the elevation profile.   I know that at one point I had a route longer than the profile showed, and the profile was cut off vertically as well.

[EDIT: as I was compiling the info for my bug report to RWGPS I found that there seems to be a connection.  Undo one time messes up the elevation profile but does not remove the segment; Undo a second time removes the segment.  Using Redo once restores the segment and the corrupted elevation profile, Redo a second time corrects the profile.  I also saw it draw the route in the correct color momentarily then re-draw on top of it on the old, now-incorrect color.  It was consistent in that.]

Looks like it's time to carefully document our findings and open a bug report with RWGPS.  Now I know how I will spend my day!  :)

Thanks everyone. 

I have now.  Sent in a step-by-step process (software test plan- I used to do software testing as one part of my job so they're getting what I think is a more-detailed-than-average bug report...) that yields the result I and others have observed.  We'll see what happens next.

Good morning Kelly-

I tried every single base map option but could never get the wrongly-colored route segment to draw in the correct color.

I did find that if I used Undo to remove the segment, selected the new color, then re-found and routed to the destination as a new route calculation (as opposed to simply using the "Redo" function) that it *usually* drew the segment in the proper color.

I wonder whether the road closure information is carried with the routing data that accompany whatever base map you are using at the moment?  That would make some sense, and would explain why some sources (Google, RWGPS) "honor" seasonal / ephemeral closures while others (OSM, USGS, etc.) that do not include near-real-time data updates are unaware of them.

And you are, of course, correct sir!  Even though this is a holiday weekend I got the following reply a few hours after I filed my report:

Hey Keith

XXXX here, thanks for writing in.
I was able to reproduce this bug with your report. I appreciate you bringing it to our attention. 
I've alerted our developers for their awareness. I'm not yet sure of a timeline for this to be fixed, but will reach out again when it is resolved.
If you have any additional questions, let us know and we'll be happy to help.

So, it's now officially in the RWGPS bug fix queue.

Thanks to all who responded that they had seen the same issue.  The first step in diagnosing an issue is verifying that it really exists and can be reproduced by a known / specified set of steps.

I change line colours by highlighting/selecting the relevant section in the elevation profile at the bottom of the page, then editing via the boxes on the right.

Also, I compile all the maps for one tour vis the 'Collections' function of RWGPS, tick the map box and the collection is headed by a composite map which shows each day in a different colour (below).  So far, I've only been to use the map elsewhere by way of a screenshot and further manipulati0n.

Bob!  Nice to hear from you.

It appears, as befits your sterling character, as though you may have the Premium level membership to RWGPS.  Those of us such as myself who live more humbly in the lower strata of society at the Basic subscription level are denied access to the "Change Color" feature when selecting route segments from the elevation profile.  But it's nice to know that it could be done.

I've got a Collection going for the big trip and have put all of the individual daily routes I've created so far in there, along with the route overview and some of the shorter multi-day shakedown routes I'm noodling over.  I see that the individual days are indeed drawn in a rainbow of colors on the collection overview map, which has the pleasing side effect of telling me exactly where I left off detailed route planning.  

Thanks for the tip, and here's hoping all is well in Oz.