Clutch pedal without pressure – kind of weird…

Hello, the clutch of my coupé (C123/230CE) suddenly behaves quite strangely. The car recently stood up for about 6 weeks – but before the clutch functioned completely unobtrusively – a week ago I first noticed in the garage that the clutch pedal felt funny soft and resistanceless. When driving it was noticeable that the clutch was coming very early, so much earlier than before. After a short ride, however, the whole thing completely normalizes again; also in the stand the pedal pressure is normal again, the clutch is used to tight. The effect showed up today, after about a week of service life again. The clutch is only four years old and has not yet 5’000 km on the hump – so what could it lie about? Thank you in advance! MfG Jablonski