You’re right! 2013.2076 is OK.
So something happened between the last public release and this one.
build 2076:
2013-12-15 00:41:32.357 Corona Simulator[22524:507] 0.055000000000007 200 50 250
2013-12-15 00:41:32.375 Corona Simulator[22524:507] 18.055 200 50 250
2013-12-15 00:41:32.393 Corona Simulator[22524:507] 35.755 200 50 250
2013-12-15 00:41:32.418 Corona Simulator[22524:507] 60.578 200 50 250
2013-12-15 00:41:32.427 Corona Simulator[22524:507] 69.281 200 50 250
2013-12-15 00:41:32.443 Corona Simulator[22524:507] 85.763 200 50 250
2013-12-15 00:41:32.459 Corona Simulator[22524:507] 101.266 200 50 250
2013-12-15 00:41:32.475 Corona Simulator[22524:507] 117.694 200 50 250
2013-12-15 00:41:32.490 Corona Simulator[22524:507] 133.117 200 50 250
2013-12-15 00:41:32.507 Corona Simulator[22524:507] 149.407 200 50 250
2013-12-15 00:41:32.523 Corona Simulator[22524:507] 165.212 200 50 250
2013-12-15 00:41:32.538 Corona Simulator[22524:507] 181.148 200 50 250
2013-12-15 00:41:32.554 Corona Simulator[22524:507] 197.111 200 50 250
2013-12-15 00:41:32.571 Corona Simulator[22524:507] 200 200 50 250
I think it’s best if you could file a bug report with your code above.
(You can add a print(t,tMax,start,delta) at the beginning of your transitionF function to display the problem)