The sample size of thirty people is going to be too small and the two year duration is too short.

I expect that participants will be happier than average and feel more secure. On the flip side they will continue working and their lives will not change much because they can see the payments will be terminated reasonably soon.

Even with the small sample size they are splitting the trial between two locations and trying to make it representative (whatever that means). This seems to raise the risk of a lot of anomalies.

I struggle to see how any meaningful conclusions would come out of this.