QApplication::setOverrideCursor causes crash on Mac

The following crash trace occurs reliably in my application, under 5.2.0 RC1, but NOT under 5.2.0 beta1, so hopefully that is a good clue as to what might be causing it – I tried various ways to replicate in a simple standalone app but was not able to do so – it seems to depend on my application driving gui updates while it runs, after the cursor has been set by QApplication::setOverrideCursor to a busy cursor. when I remove that call at the start of running, there are no crashes.

Here's the trace:

• thread #1: tid = 0xb3616f, 0x00007fff96ba522b libobjc.A.dylib`lookUpImpOrForward + 129, queue = 'com.apple.main-thread, stop reason = EXC_BAD_ACCESS (code=EXC_I386_GPFLT)
  frame #0: 0x00007fff96ba522b libobjc.A.dylib`lookUpImpOrForward + 129
  libobjc.A.dylib`lookUpImpOrForward + 129:
  -> 0x7fff96ba522b: testb $1, (%rcx)
  0x7fff96ba522e: jne 0x7fff96ba5237 ; lookUpImpOrForward + 141
  0x7fff96ba5230: movq (%r15), %rax
  0x7fff96ba5233: movq 32(%rax), %rax
  (lldb) bt
• thread #1: tid = 0xb3616f, 0x00007fff96ba522b libobjc.A.dylib`lookUpImpOrForward + 129, queue = 'com.apple.main-thread, stop reason = EXC_BAD_ACCESS (code=EXC_I386_GPFLT)
  frame #0: 0x00007fff96ba522b libobjc.A.dylib`lookUpImpOrForward + 129
  frame #1: 0x00007fff96b98169 libobjc.A.dylib`objc_msgSend + 233
  frame #2: 0x00007fff97cbf928 AppKit`-[NSWindow sendEvent:] + 6208
  frame #3: 0x000000010c50bb75 libqcocoa.dylib`-[QNSWindow sendEvent:] + 53
  frame #4: 0x00007fff97ce10ac AppKit`handleCursorRect + 192
  frame #5: 0x00007fff97c5f628 AppKit`-[NSApplication sendEvent:] + 1737
  frame #6: 0x000000010c51ca1e libqcocoa.dylib`-[QNSApplication sendEvent:] + 78
  frame #7: 0x000000010c518d4d libqcocoa.dylib`QCocoaEventDispatcher::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) + 1021
  frame #8: 0x0000000101e04f8e QtCore`QCoreApplication::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) + 30