Notation for holding a finger down across notes (for beginners)

In my son's beginner cello music, there is a notation that looks like modern on/off pedal notation (like a square bracket rotated 90 degrees -- see attached). He tells me it means to hold down the starting finger until indicated.

Visually, this is exactly the same as one of the pedal symbols in Musescore. However, on playback, the sustain is performed, which is annoying.

I don't suppose there is a way of producing this symbol without the playback side-effects? (Maybe the playback effect should only be used when the patch is for an instrument with a sustain pedal?)