> Any economic policy that changes prices can be seen as inflationary if you pick the right index. The CPI is not what matters. What matters (to workers) is the ratio of the CPI to wages.
Since UBI isn’t likely to drive wages up (and, if as often proposed it replaces or offsets minimum wage, it may drive them down at the low end), I don’t see any real difference there, even if it was correct (I agree that what matters to workers qua workers is real [that is, CPI-adjusted] wages, and to consumers qua consumers real income; but that doesn’t alter the definition of inflation, just notes the inflation per se is not the concern for those groups in those roles.)
UBI is likely to lead to inflation, is unlikely to lead to general real wage increases (though that’s complicated), but will lead to real income increases in the low end of the distribution unless cranked too high high too fast (and there are negative feedback controls that should avoid that problem unless deliberately subverted, say by indexing UBI to inflation.)