Sometimes there are reasons, just you didn't notice it. I found I block much more after drinking more than 250mg caffeine worth of coffee (really sad as I really enjoy coffee...), so perhaps any substance that can cause potential stress attribute to stutter? Also, subconscious stress or pressure may be a thing even if you are not experiencing any conscious stress. Do you get angry more often? Sleep worse? Have more darker thoughts than usual? All these can be cues for subconscious stress. Idk what is causing it, but I genuinely wish it gets better for you soon!