Theta vs Decay in Options in Sensibull

@Sensibull, my questions may appear too basic, so pls bear.

There are two columns, theta and decay.

It says “theta value is change in P&L after one day if nothing else changes”.

And decay is “Time value decay due between now and the next market open if everything else stays the same”

If today is Thursday and tomorrow Friday is not a holiday, why there is a difference between theta value and decay value