a workaround is to recreate your delayline in prepare() according to the new max size when needed (i.e when it increases):
delayLine = std::make_unique<juce::dsp::DelayLine<float, juce::dsp::DelayLineInterpolationTypes::None>> (maxDelayInSamples);
On a side note a method to get the current max size would be useful (there’s an other FR here about that)