Thank you very much.
The problem is on my code but basically they're 2, first is that I'm using a pseudorandom algorithm to generate the positions, so the bucko will always be on the same position every time aka the 26th position.
The second is that the collision check is the hardware collision check from the c64 video chip and it's checking the collision of the sprite with the text too, you can see that everytime it locks, it's because the bucko or heart is above some text.
I'm gonna publish a patch tomorrow to fix it, I just don't know when