The ability to name layers and layer groups was introduced in Sketchbook iOS version 6.0.
A bug with the text encoding meant that some text characters would be incorrect when opened in other versions of Sketchbook and Sketchbook Pro.
The text encoding has been fixed in Sketchbook version 6.0.3.
A side effect of this fix is that names with affected characters will appear incorrect/garbled after the update
If this has happened to your file, please edit the layer and/or group names to be correct. You will only have to fix them one time for the encoding to become correct. This problem will not reappear.
If you have any questions, please reach out to us at firstname.lastname@example.org