Leaked Curia poll pretty terrible sign for National (Patreon)

Polls are a snapshot in time. One poll is pretty unhelpful, you need multiple polls to get a trend. Internal polls are also notoriously unreliable. I've been leaked several of Labour's internal polling but that's usually when it suits Labour.
This time I was given the (alleged) poll results of National's internal polling - Curia - run by notorious KiwiBlogger David Farrar.
The numbers I was given by a normally reliable source showed a pretty dire situation for National.
Labour was on 49 - no surprise given the Prime Minister's excellent handling of the COVID-19 crisis.
National was on 31 - which is absolute crisis territory. If this plays out in September then National would lost 18 MPs and go down to 37.
ACT on 5 which is massive for them, given where they've been. Their active courting of the White Supremacist vote and National's relative weakness has helped them it seems.
Less sure was the Greens on 9 and NZF on 6. Both of those results would please those parties immeasurably given that Jacinda Ardern is sucking up all the oxygen.
Poll result:
Lab: 49
Nat: 31
Green: 9
NZF: 6
ACT: 5
This is quite a bit different from a Labour internal poll that circulated a couple of weeks ago which was:
Lab: 49
Nat: 35
Green: 5
NZF: 5
ACT: 2.2
Though not hugely different.
It's still 5 months out from an election, and a very strange time indeed so not a huge amount can be read into this but it is nonetheless interesting to see how New Zealand has reacted to the lockdown. It doesn't seem that Labour has benefited, but rather that National voters have fled from Bridges.
Whenever I'm leaked a poll, it's always worth asking "why was I leaked this, and who stands to gain/lose from it?"
In this instance I think it's pretty clear that someone is very displeased with Simon's performance.

UPDATE 16 APRIL: An internal poll from Labour also has National under 35 suggesting this is where the country is right now.