Someone else reported this, and said the character became visible again after teleporting.
If you wish you can email supportdos@larian.com, with a description of the problem and the report.zip file generated by the
D:OS support tool (for the PC version). The report will contain system and game information, any crash dumps, and your saved games (all but one, with your invisible character, can be deleted to reduce the zip's file size, if needed).
This is a know issue, but not consistent, so it wouldn't hurt to have more information.
