A serious distinction is that increased minimum wages incur a burden on employers which they pass around to their customers and business partners. The increase of burden is directly proportional to the amount of work of an hourly employee. UBI does not come from an employer and is not tied to an effort. There is no direct market burden, but yet an increase of cash is available none the less.
It should also be noted that inflation is not immediately present following a cash stimulus. It takes time for inflation to set in as a response to market conditions and as such inflation is measured as an adjustable change over a given period of time. That said specific single time examples of UBI not adjusting inflation only demonstrates a faulty understanding of economics.