I don't see why those caps don't work right. Maybe it
is the temperature since the traces may get quite warm and the heat will tend to be sinked through them.
High speed caps would be more of an issue for oscillator or high frequency filter, but I think (please correct me if I'm wrong) those caps are actually to provide a little amperage oomph during high current spikes.
Anyway, it will be interesting to see how those new caps work. If you are concerned about the working voltage, I found some inexpensive ones
here. Temp ranges from -40 to 85C. These are from partsexpress so they tend to use the higher quality caps for use in audio crossovers so they may be faster switching as a result even though they don't specifically say that.