Didn't Springbank mature some malt in ex-rum or ex-port pipes (can't remember which) and the whisky came out green? Not all finishes work. I was discussing this with Bill Lumsden from Glenmorangie a bit over a year ago, and he confessed that many of the finishes they try are deemed unsatisfactory and unsuitable for bottling.
I'm sure all manner of casks are in circulation around the place, Frodo, and no doubt all sorts of different wines or spirits have been previous occupants. With the exception of unique finishes, or single cask bottlings, this underscores the important need for marrying, etc, prior to bottling, in order to iron out all that variability.