It may be very useful that Notion automatically divides the notes that fall between a measure and the other, as Sibelius and Musescore do, instead of marking them in red.
For example, in a 4/4 stave, you put a 1/4 note, then a 2/4 note; if you put another 2/4 note, Notion picture it in red because the total timing (5/4) exceed the time signature; Sibelius and Musescore, however, automatically divides the 2/4 note in a 1/4 note , write another 1/4 note in next measure and put a tie on both, restoring its initial value (2/4).
This is useful ever when copy/paste groups of notes that have total value different from the value of the measure.