The tool download here on Hive has been updated with a fix, version 4.6b. Feel free to do some testing with it and report any issues.
As a note, we don't have to be shattered by surprise updates with regards to Retera Model Studio. The program is open source hosted here:
GitHub - Retera/ReterasModelStudio: Retera's Java WC3 libraries.
95% of the code changes to fix the new issue were written by
@BogdanW3 this morning and not by me. Because the code is available, you could be the one to do the fixes as well if you desperately need them. This is a different style of code management than Blizzard Activision's game, which is the only place where surprise updates are faced. For a fan tool like this, we can have shared access to fix the tool so that if it breaks you can always fix it. I like this style better. If I have a heart attack, someone else could always still fix it. So Retera Model Studio is never going to be "taken away from you" unless you decide to start using a version that is not open source.