utf8 collections can't be negative-indexed

For some reason (??) this collection isn't bidirectional (or not anymore?)
5 jobs for master in 2 minutes and 9 seconds (queued for 1 second)
Status Job ID Name Coverage
  Test
passed #4178
autoscale-linux
linux

00:01:55

passed #4176
xc7 openswift atbuild
osx

00:00:05

passed #4177
xc7 openswift atbuild
osxxcode

00:00:04

 
  Package
passed #4180
xc7 openswift atbuild package-framework
ioscorepackage

00:00:02

passed #4179
xc7 openswift atbuild package-framework
osxcorepackage

00:00:02