I changed my 0.4mm nozzle to a 0.25mm nozzle and calibrate my printer to obtain a decent first layer. To try this new configuration, I printed a benchy, the everyone favorite 3d printer murdering boat. It did not fail, the whole object has been print, without stringing, oozing or warping. However, an issue between some well print layer has occurred. I do not understand what happened. Did someone have an idea about the cause of this failure?

You can find two picture below or there: https://imgur.com/PATrswW and https://imgur.com/RcoAp8p