It means you already had the paycut, you need to have at least %4.2 rise + reimbursement to make even.
In high inflation countries you often get a revision every 2-3 months and you get a rise that is higher than the official inflation, as a result this solidifies the inflation and boosts the economy as everyone immediately buys whatever they can before it becomes more expensive. It's a vicious cycle.
Reminds me of stories from ex-Yu during high inflation periods (e.g. yearly doubling; not counting periods when there were runaway spikes of almost daily doubling) when people would go to remote areas where shops didn't yet get the updated prices from headquarters and basically walked away with a bunch of near free stuff.
Small independent shops are often having trouble with keeping up with the prices, so checking out those shops sometimes yields great deals.
They should clearly buy e-ink price displays! /s
You and your employer should consider future expected inflation at the time of negotiation. You don't need a true up in that case to "break even!.
IRL most of the time there's no negotiation, you find out your updated salary when the money hits the bank.
At initial employment there is salary negotiation. Each COLA then automatically inherits whatever assumptions were baked into the starting number.
Argentina, for example. Coworkers there told me about this. Madness.