Can't modulate `Vib LFO freq` slowly

[yukulele]

FluidSynth version

FluidSynth runtime version 2.2.5 Copyright (C) 2000-2024 Peter Hanappe and others. Distributed under the LGPL license. SoundFont(R) is a registered trademark of Creative Technology Ltd.

FluidSynth executable version 2.3.5 Sample type=double

Describe the bug

I have a sf2 file with a modulator CC-01 Modulation wheel to Vib LFO freq.

When I slowly modulate CC-01 from 0 to 127 LFO seem to be stopped

Expected behavior

The LFO should gradually become faster and faster. (as Polyphone does)

Steps to reproduce

• open sample-LFO-freq.sf2 with fluidsynth
• start playing a note
• slowly vary the modulation wheel from 0 to 127