It depends how it's funded. Strictly speaking that's only the case if it's funded monetarily by a central bank printing more money for a government to fund UBI. For example this is how most countries funded businesses and individuals during the pandemic and what has lead to the inflation you're referring to. Otherwise there is the same amount of money in the economy, it's just been fiscally re-distributed using a UBI policy. You might still see some inflation in some parts of the economy due to rising demand but if people can afford more, rather than less, this inflation no bearing whatsoever on people's actual prosperity. If funded fiscally UBI would outstrip any inflation it might incur and therefore actually represent real-terms deflation for the vast majority of people. As a side note, what we are getting at the moment is the exact opposite: money was printed in huge amounts by central banks during the pandemic which largely ended up in the pockets of people who bought up assets like housing and are now out-competing everyone else in the market and extracting yet more profit. It might feel like inflation to us because food and bills have increased in value faster than our wages, but the wealthy have actually been experiencing real-terms deflation because their stash has been growing faster than their costs.