The amount given to residents is based on a formula that is regulated by the state government. Any amount of the resident portion that is not given to the residents is reinvested into the Permanent Fund where it cannot be touched. However, by reinvesting a portion of the resident allotment (or the state government allotment--but that never happens), the Permanent Fund grows and will more likely have a greater payout (to the three divided amounts) the following year(s). Although the government cannot touch the Permanent Fund itself (although it routinely tries to sneak amendments through), it can reduce the amount given to residents as part of the aforementioned reinvestment strategy. This has been the case for the past three years.
The current governor ran on the platform of giving every resident their full PFD each year, plus repaying them for the shortened PFDs from the past three years. However, he cannot pull this money from the Permanent Fund itself (without a constitutional amendment). Instead, he is pulling the money from the portion of the dividend that would normally go to the state government to spend, effectively drawing the money from the general funds which should otherwise go to education, medicaid, mental health programs, prisons, fire and safety, etc. With his current budget, he has promised to pay back an extra $1,061 this year, $1,289 next year, and $1,328 in 2021. These amounts alone account for an approximate $680 million of this year's shortfall, $800 million of debt for next year, and $840 million of debt in 2021.
The governor has been careful to say that the 2019 PFD distribution has nothing to do with this year's budget shortfall of $1.6 billion. However, he conveniently does not mention the repayment debt when saying this. In fact, his office has been careful to differentiate between the PFD distribution and the repayment plans. It's an interesting word game used to hide the fact that this repayment is coming at a direct cost to our medical, safety, and education systems.
Sure, this doesn't solve the entire budget deficit (the $2 billion in oil tax credits could easily handle that), but it would make a significant dent in it.