Use only containers specified as suitable for freezing the intended food. An ordinary jar may not tolerate the temperature change or expansion of its contents.
What the observation tells you
A screw lid can conceal pressure from overfilling until the glass cracks. Frozen food may then contain fragments that are hard to see. Leaving extra space is important but does not turn an unsuitable jar into a verified freezer container.
A useful next step
Choose appropriate packaging and follow its filling guidance. Keep labels and dates clear. If glass breaks, do not pick fragments from food and assume the remainder is safe; handle the contamination and damaged container cautiously.
Manuals and supporting guidance
Model-specific instructions take priority. These references support the practical principles discussed here; they do not diagnose your appliance.