Config beforehand:
<nat-config xmlns="urn:ietf:params:xml:ns:yang:ietf-nat">
<nat-instances>
<nat-instance>
<id>0</id>
<external-ip-address-pool>
<pool-id>180581228</pool-id>
<external-ip-pool>10.195.115.108/32</external-ip-pool>
</external-ip-address-pool>
<external-ip-address-pool>
<pool-id>180581226</pool-id>
<external-ip-pool>10.195.115.106/32</external-ip-pool>
</external-ip-address-pool>
<external-ip-address-pool>
<pool-id>180581227</pool-id>
<external-ip-pool>10.195.115.107/32</external-ip-pool>
</external-ip-address-pool>
<external-ip-address-pool>
<pool-id>180581224</pool-id>
<external-ip-pool>10.195.115.104/32</external-ip-pool>
</external-ip-address-pool>
<external-ip-address-pool>
<pool-id>180581225</pool-id>
<external-ip-pool>10.195.115.105/32</external-ip-pool>
</external-ip-address-pool>
<external-ip-address-pool>
<pool-id>180581222</pool-id>
<external-ip-pool>10.195.115.102/32</external-ip-pool>
</external-ip-address-pool>
<external-ip-address-pool>
<pool-id>180581223</pool-id>
<external-ip-pool>10.195.115.103/32</external-ip-pool>
</external-ip-address-pool>
<external-ip-address-pool>
<pool-id>180581220</pool-id>
<external-ip-pool>10.195.115.100/32</external-ip-pool>
</external-ip-address-pool>
<external-ip-address-pool>
<pool-id>180581221</pool-id>
<external-ip-pool>10.195.115.101/32</external-ip-pool>
</external-ip-address-pool>
<mapping-table/>
</nat-instance>
</nat-instances>
</nat-config>

And this is what we're trying to configure:
<nat-config xmlns="urn:ietf:params:xml:ns:yang:ietf-nat">
<nat-instances>
<nat-instance xmlns:a="urn:ietf:params:xml:ns:netconf:base:1.0" a:operation="replace">
<id>0</id>
<external-ip-address-pool>
<pool-id>180581228</pool-id>
<external-ip-pool>10.195.115.108/32</external-ip-pool>
</external-ip-address-pool>
<external-ip-address-pool>
<pool-id>180581226</pool-id>
<external-ip-pool>10.195.115.106/32</external-ip-pool>
</external-ip-address-pool>
<external-ip-address-pool>
<pool-id>180581224</pool-id>
<external-ip-pool>10.195.115.104/32</external-ip-pool>
</external-ip-address-pool>
<external-ip-address-pool>
<pool-id>180581225</pool-id>
<external-ip-pool>10.195.115.105/32</external-ip-pool>
</external-ip-address-pool>
<external-ip-address-pool>
<pool-id>180581222</pool-id>
<external-ip-pool>10.195.115.102/32</external-ip-pool>
</external-ip-address-pool>
<external-ip-address-pool>
<pool-id>180581223</pool-id>
<external-ip-pool>10.195.115.103/32</external-ip-pool>
</external-ip-address-pool>
<external-ip-address-pool>
<pool-id>180581220</pool-id>
<external-ip-pool>10.195.115.100/32</external-ip-pool>
</external-ip-address-pool>
<external-ip-address-pool>
<pool-id>180581221</pool-id>
<external-ip-pool>10.195.115.101/32</external-ip-pool>
</external-ip-address-pool>
<mapping-table>
<mapping-entry>
<index>0</index>
<internal-src-address>10.100.0.9</internal-src-address>
<type>static</type>
<external-src-address>10.195.115.107</external-src-address>
</mapping-entry>
</mapping-table>
</nat-instance>
</nat-instances>
</nat-config>

Commit fails with operation-failed and hc logs show "Caused by: io.fd.vpp.jvpp.VppCallbackException: vppApi.snat_add_address_range_reply failed with error code: -6". -6 means _(NO_SUCH_ENTRY, -6, "No such entry")

Detailed logs attached