FLOATS_VWALK with nested application

[Hilberthotel]

Hi,
I am running a two-way nested grid application with 3 times refinement and floats in the refined grid. Just defining FLOATS works fine but as i try to add a vertical random walk for the particles my simulation is stuck after the first exchange step (STEP 0) and I get the error:
forrtl: severe (151): allocatable array is already allocated
I tried to find all allocations of the floats-arrays within the code but could not find where FLOATS_VWALK or VWALK_FORWARD might introduce a false second allocation.
Unfortunately running in debug mode does not give me more info where the problem might be. Does anyone else ran into this issue and knows maybe how to solve this?
Regards,
Flo