homework and exercises - Relative acceleration of bodies on opposite sides of a pulley

This is a problem that I encountered while solving problems related to constrained motion:

With all the data given in the above question, I believe that the monkey just holds on to the rope and does not climb it up or slip down. So if that is the case , and assuming that the string is inextensible, shouldn’t the monkey and the block have the same accelerations? However, when I saw the solution to the above problem, the monkey and the block have different accelerations. How is that possible?