Twice in last three days 235 has stopped mapping in middle of run and appears to just guess the distance. Friday I ran a measured 16 and it gave me 14+ but only mapped a portion of that. Sunday I ran 17 and change I think and it gave me over 18 but only mapped four miles. This has happened a couple times in the last fe years but twice this week and a third time ten days ago is making my GPS a very expensive bracelet. Anyone have this happen to them of have a fix?