Muted Brass instruments are cut short in playback

Hi,
I swapped this week from Musescore 3 to 4.
I imported my British Brass Band Scores from 3 and realized that muted Brass Instruments get cut a bit short, where in Musescore 3 they were held through. It sounds now as if every muted note is articulated, even tho it should be slured or legatissimo.
Even with an added Legato, it still articulates the notes.

Not too big of an issue to compose, but it just sounds strange when a held through passage has holes in them.

Attached you find an example of this with File and Exports from 3 and 4 respectivley.