Despite being fully signed, none of 131 west of the Jordan River is open. This will likely be the case for the next year or more until they finally build the damn bridge. I don’t understand why it’s signed so well at Redwood, but whatever.
As of May 2020, when I was last in that area, the east side of 131 is open from 140 down to Harmon Day Drive. I did not see any 131 signs yet in that area, but they may be waiting to improve route signage over there until 131 is complete and/or it’s clear what is ultimately going to happen with 140. That one has a very odd west end right now and my bet is that UDOT would like to get rid some/all of what’s left of it.