As per the release notes, the staking reward mechanism has changed in release 0.50.3 which was recently deployed to mainnet by the validators.
The changes introduce a new automated transfer type for funding reward pools that prepares the network for the launch of Alpha Mainnet with trading. They also include the ability to automatically apply a decay factor to reward transfers. This will be used in future to align rewards with the long term token supply curve.
To test this new functionality, the protocol will distribute a test reward of around 100 VEGA per day for 2 epochs to ensure the new process is functioning correctly, before returning to normal levels on Friday.
To ensure total rewards are not impacted as a result of this testing, the reward pool was configured with 3 times the normal epoch rewards prior to the network upgrade. These were distributed at the recent epoch end. The total rewards distributed over these 3 epochs will therefore be slightly above the usual level.