I've experienced the same crash -- having to adjust the bottom of a text box. But I don't think the problem is with InDesign CC2015. Because just as you did, once the file is saved as an IDML file and re-opened, it works fine. I think there's some sort of "crud" that's in the code with documents that were started with one version of InDesign and then worked on with a newer version. For whatever reason, saving as IDML and reopening clears out all the crud, regardless of CC2014 or CC2015.
I think there are still quite a few bugs in ALL the releases of InDesign, but CC2015 doesn't appear to be any worse than CC2014 (which is hardly a glowing endorsement, but it could always be worse!).