testbench manual test crashes on iPad when changing orientation

It doesn't always happen, but in maybe 4 of 5 cases.

Console output after starting (not sure whether this is related):

QML debugging is enabled. Only use this in a safe environment.
2015-12-17 10:07:47.132 testbench[207:5217] <CATransformLayer: 0x16585a10> - changing property masksToBounds in transform-only layer, will have no effect
2015-12-17 10:07:47.137 testbench[207:5217] <CATransformLayer: 0x1660a100> - changing property masksToBounds in transform-only layer, will have no effect
2015-12-17 10:07:47.139 testbench[207:5217] <CATransformLayer: 0x16608fd0> - changing property masksToBounds in transform-only layer, will have no effect

Console output when crashing:

program received signal -111, thread:1475;name:QSGRenderThread;qaddr:4029b100;00:01000000;01:efbeadde;02:feffffff;03:00000000;04:00000000;05:08000000;06:5df64f24;07:58aa2940;08:01000000;09:90010000;0a:00f05b05;0b:6be95b05;0c:7c032d38;0d:30aa2940;0e:c7bd692e;0f:a2b2692e;10:30000000;metype:1;mecount:2;medata:1;medata:1;
program received signal -111, thread:1475;name:QSGRenderThread;qaddr:4029b100;00:01000000;01:efbeadde;02:feffffff;03:00000000;04:00000000;05:08000000;06:5df64f24;07:58aa2940;08:01000000;09:90010000;0a:00f05b05;0b:6be95b05;0c:7c032d38;0d:30aa2940;0e:c7bd692e;0f:a2b2692e;10:30000000;metype:1;mecount:2;medata:1;medata:1;
program received signal -111, thread:1475;name:QSGRenderThread;qaddr:4029b100;00:01000000;01:efbeadde;02:feffffff;03:00000000;04:00000000;05:08000000;06:5df64f24;07:58aa2940;08:01000000;09:90010000;0a:00f05b05;0b:6be95b05;0c:7c032d38;0d:30aa2940;0e:c7bd692e;0f:a2b2692e;10:30000000;metype:1;mecount:2;medata:1;medata:1;
program received signal -111, thread:1475;name:QSGRenderThread;qaddr:4029b100;00:01000000;01:efbeadde;02:feffffff;03:00000000;04:00000000;05:08000000;06:5df64f24;07:58aa2940;08:01000000;09:90010000;0a:00f05b05;0b:6be95b05;0c:7c032d38;0d:30aa2940;0e:c7bd692e;0f:a2b2692e;10:30000000;metype:1;mecount:2;medata:1;medata:1;
program received signal -111, thread:1475;name:QSGRenderThread;qaddr:4029b100;00:01000000;01:efbeadde;02:feffffff;03:00000000;04:00000000;05:08000000;06:5df64f24;07:58aa2940;08:01000000;09:90010000;0a:00f05b05;0b:6be95b05;0c:7c032d38;0d:30aa2940;0e:c7bd692e;0f:a2b2692e;10:30000000;metype:1;mecount:2;medata:1;medata:1;
program received signal -111, thread:1475;name:QSGRenderThread;qaddr:4029b100;00:01000000;01:efbeadde;02:feffffff;03:00000000;04:00000000;05:08000000;06:5df64f24;07:58aa2940;08:01000000;09:90010000;0a:00f05b05;0b:6be95b05;0c:7c032d38;0d:30aa2940;0e:c7bd692e;0f:a2b2692e;10:30000000;metype:1;mecount:2;medata:1;medata:1;
hit maximum number of consecutive signals, stopping