Why GPS in 5 plus is SO bad (SOLVED)

So Ive just finished the Blackmores Sydney Half Marathon today and logged a 22.39km run over what should have been 21.098 whilst using GPS+Galileo. Something's clearly gone wrong. Looking at the plots, we see an excellent visual demonstration on the impact of tall structures on perceived GPS coords. You can see the reflectance of the buildings in the first screen cap as we were moving through the CBD and a comparatively accurate plot in the second during the park run section.

I've tried configuring GPS to lock to roads and this gives me an accurate plot on the watches map, but still results in a skewed pace and errant GPS data when uploading to Strava. It's a bit of a shame Garmin can't seem to combine the accelerometer and compass data to validate the delta from the last coord and discard the obviously anomalous readings such as those seen on the first screen cap.

Were these three recorded at same time? 

So finally I've installed 2.51 beta GPS update. Tracks looks better now in some extent; meaning not so ugly as used to be but still not so realistic as a track from smartphone or Polar. On other hand, on the 200m intervals it seems F5+ correctly counts laps. I also compared a plot after update from the latest parkrun with the plot from M400. Definitely, F5+ looks better now (note M400 out of the track places marked by red arrows). So 2.51 is not HUGE step forward but considerable; now my F5+ is not on sale anymore

No, all my tracks are recorded at different times.

OMG Joel, it is even worse than my example. That is really odd - as soon as I know, reflections handling was a part of GPS devices for the very long time. Sophisticated devices as high-end Garmins should be able to fight with them. Unfortunately I can't share my experience for that conditions - I never run near tall structures. My "reference" 200m track has perfectly open sky with no tall buildings nearby. 

Thank you Alan. Do you mean this part? It looks good for me, doesn't for you? Two laps however probably is not so representative. Note that my track has proper "shape" overall. The problem comes with counts - shape becomes a ball as wrong laps accumulate.  

Progress! Small, but better than nothing! Hope it gets better bud

до покупки F5+ пользовался 735,проблем с GPS не испытывал, решил взять F5+ и пожалел, через раз получал  трек (вид занятия бег)  как на картинке обведённой жёлтым, дико бесило, но нашёл причину плохих треков и стал получать как на картинке слева,  вся причина - это в каком направлении "смотрят" часы, так  или так 

короче, если часы все время смотрят вверх проблем ни с треком ни с измеряемым темпом нет, как только в пол и в стены зданий - записанная тренировка на смарку.