Washout corrections

From your overview:‘Washouts often severely affects log measurements and it is therefore very important to determine bad hole sections in order to reduce the weighting of the log values in the training.’
Why washout correction is needed? I thought that borehole size corrections were already done for all tools. Or we need extra quality control of logs? For now, the one way to check logs for washout is to use ‘Density Correction log’ and ‘Differential Caliper Log’. Am I right?