Steps to reproduce:
# Open any scene
# Open the Task Manager and view your GPU memory utilization
# Add some probes
# Crank the lighting settings (such as probe multiplier) to make the allocation sizeable (depending on your GPU). 
# Make sure you're using the GPU Lightmapper
# Hit 'generate lighting'
# Wait until you see the VRAM allocation happening (should be a steep hump in the video memory utilization)
# Allow the bake to finish (see that the memory is indeed deallocated)
# Initiate another bake
# This time, before the `Baking` step is done, but after the allocation has finished, hit `Cancel` in the Lighting Window.
# Notice how the memory is not cleaned up.
# Hitting `Generate Lighting` again will allocate even more memory.
# Repeat generate-cancel as many times as you see fit, it will keep stacking memory.

Notes: The LightBaker process is properly cleaned up. This reproduces only with LightBaker and LightProbes in 2023.2 and 2023.1. It also affects APV.