BIG-IP CGNAT with PBA - Clear/delete a PBA block

tl;dr - How can I delete a PBA block allocated to a specific client unde the CGNAT module?

Hello guys! Hows everybody?

I'm working on a CGNAT PoC with a client. Currently we're running v12.1.3 on a VE.

The LSN pool is configured as PBA with 512 ports in each block. Everything works fine.

Since it's a PoC there are a lot of tests we do. And I tryed to find a way of clearing/deleting the current block allocated to a specific client.

lsndb list pba shows the current block assigned to the client as follows:

[root@bigip1:Active:Disconnected] config  lsndb list pba
LSN port block allocations
Client                                              Port block                                          TTL
-------------------------------------------------------------------------------------------------------------
10.0.1.100                                          192.168.1.10:2048  - 2559                           271
1 port block entry found.

When I try to delete this block so I can test one more time, I get an error:

[root@bigip1:Active:Disconnected] config  lsndb del pba
Error: PBA entries cannot be deleted

Deleting the client's connection with 'delete sys connection cs-client-addr 10.0.1.100' clears the connection table but not the NAT block.

Question: Is there a way of deleting this entry for the PBA block allocated to the client? If yes how? I looked everywhere I could think of... I know I can configure a timeout (and actually this is what I'm doing right now to speed things up) but when this thing goes live I'll have to configure a longer timeout and this is not a real solution I think...

Many thanks! Rafael