Fenix GPS accuracy

I run with friends, many also have Garmin watches.  I notice mine is usually the least accurate, weaving me in an out of buildings and such.  I know running among tall buildings, trees, etc can confuse the GPS.  However why would mine do that consistently more than my friends' watches?  It doesn't matter if we are running all together or spread out a bit.

My watch is updated etc.  I've tried it with just GPS as well as with GPS and Glonass turned on, that doesn't help.  

Here's from last night's run.  Mine on the left and a friend's on the right.  His got a bit confused, but mine far more.  It's consistently this way.  Makes me wonder if there is something in setting or elsewhere that I could change to improve accuracy.  

any thoughts?  

Thanks