Absolutely. Since that VCA module has no input attenuation, it's a good bet that some audio sources are overloading it as not everything in Eurorack is exactly the same as far as peak-to-peak voltages go. Also, given that these are exponential VCAs, there's also a good possibility that deeper swings in CV will also push the VCAs into overdriven ranges since the linear curves of the LFOs are going to be 'misinterpreted' as exponential-type signals. Exponential VCAs really are best controlled with envelopes, and offer a quick and dirty way of using linear EGs to get exponential responses.