1.1.3 actually fixed a bug that was making chains break more often than they should, which in turn broke my code, and I didn't notice it.
I've now changed the approach used in my code to account for the fix, and it should be working again. I just tested the new code by chaining 40 dittos while always defeating them and going for the closest shaking grass, so either I pulled off the luckiest chain in the world or the code is working again.
Edit: just to be clear, the code was only tested on Pearl 1.1.3.
Code:
[Chain won't break (v1.1.3)]
04000000 01E4C7A0 6B0803FF
04000000 01E4E1CC 52800020
[Chain won't break (Off) (v1.1.3)]
04000000 01E4C7A0 6B08001F
04000000 01E4E1CC 52800C80