When I try this trick, it just doesn't find the collision. even when it should take just a second, it never finds it. can you confirm these are the steps you did?
Choose a range (say, 48 bit)
Choose any key that is not in that range
run kangaroo on it for some time, (with -m 3 to be exact to your example), and make it save the work into a workfile.
Then load the work file into a new session with an actual key inside the range.
This is what I did, didn't work.
Before finding the public key in the range, did you change it in the working file using a script?
P.S. 48 bit...? Maybe you are using CPU and not GPU, then it won't work. I remade the JLP program only for GPU, I don't know who uses CPU now.
I didn't touch the workfile or changed it using a script. I did try using a CPU. I'll try now using a GPU.