I encountered this issue just before 1.6 came out so I wanted to check it with 1.6. It still exists so I thought I would submit it:
11/2/2015 - 20::55 - Assertion failure:filename:…\src\GUI_DeferredBatcher.cpp,linenum:440,build:Beta 1.15
11/2/2015 - 20::57 - Assertion failure:filename:…\src\GUI_DeferredBatcher.cpp,linenum:440,build:Beta 1.15
11/2/2015 - 20::59 - Assertion failure:filename:…\src\GUI_DeferredBatcher.cpp,linenum:440,build:Beta 1.15
11/2/2015 - 21::44 - Assertion failure:filename:…\src\GUI_DeferredBatcher.cpp,linenum:440,build:Beta 1.16