It's just something we noticed in the testing from June until now in the software that we cannot mention. I have long advocated that documentation should be released in June with the you-know-what software, but this change is probably never going to appear.
It was also noted that text tones are "smoother and quieter" by one of the test team and presumably remastered - maybe the tone sellers need to catch up and update them like any other "app". Maybe they are not even .m4r any more - who knows!
Re side loading DIY .m4r tones, it was only something I learned from TT2, not sure that was ever documented.