Sombra's new skin has issues:

[Bendubz11-2740]

Presumably it breaking on things that it’s not supposed to break on. To quote directly from the patchnotes:

@TomPowers

We’re also removing the 0.1 second window of time during a hack where it couldn’t be canceled via line of sight or with other abilities including Tracer’s Recall and Zarya’s Particle Barrier, which was originally put in place so the hack wouldn’t be interrupted by small objects such as light posts. We’ve implemented a separate fix for that issue, so she should still be unaffected by those small objects.

Bolded the bit about small objects like sign posts, they’re supposed to not interrupt hack even now, but they do.