Shortly after you joined the company, some 5 years previously, the older, wood-lined fermenting vats were replaced by stainless steel equipment and a new high-performance (high alcohol) yeast strain was introduced.
Since that time it has been found that with some batches a ‘musty’ aroma becomes detectable by ca 50% of tasters after 3 years maturation and there is concern that the character of the mature whisky is adversely affected.