NDSP said that this last update introduced a 60 ms gap when switching presets. Before the update, it was gapless. Supposedly it´s because of the added flexibility in effects. This is what they state in the FAQ section of the web:
Are there gaps when switching Presets?
With NanOS 2.0.0, Nano Cortex now introduces a very short audio gap when switching Presets. The gap is minimal, typically around 60 milliseconds, and will not interrupt delay or reverb trails, which continue naturally between Presets. This change allows for greater flexibility in the signal chain and makes room for new features and devices introduced in NanOS 2.0.0.