I came across an odd issue using the Skype for Business 2015 Office 365 ProPlus (German language) where the client would crash randomly after ending a P2P or Enterprise Voice call and the majority of the menu’s were missing the text. The menu would pop up but was blank. You could still click successfully where the text should be, however this is quite confusing to end users.
In this scenario, the exact client version was: Skype for Business 2015 15.0.4711.1002
I resolved the issue by simply applying KB3054946 (https://support.microsoft.com/en-us/kb/3054946) which updated the client to 15.0.4737.1001.