It certainly could. Depends a lot on the specifics of how the UBI is implemented, and how UBI affects salary levels. If everything remained the same and everyone just got x more income each year, then yes, inflation is very likely. On the other hand, something more like no questions asked/no demands made social security, where the only requirement is being unemployed, could improve conditions for people who are unable to work while paying for itself in eliminating heaps of red tape, and also freeing up a lots of manpower towards helping people sort out their lives instead of pouring over disability pension applications, without paying out a bunch of money to people who don't need it because they earn plenty from work already.

One could also pay out ubi universally, but have a one time down-adjustment of salaries the first year.

Right and wrong. Right if it increases aggregate demand more than available economic production thus leading to inflation.

But if we overall had capacity to tame in the added UBI, then no. Unlike targeted subsidies like EVs, UBI is do much better. Each industry is still competing with other industries