It appears that once West pitched a club on the 3rd trump and then turned up with 4 spades, a simple 100% line was available. If declarer, after 3 trumps and 2 spades, just played CA, CK, club ruff, then if West guards clubs there is a simple squeeze (cash last trump then hearts) and if East guards clubs a standard double squeeze with hearts the common suit. In practice, of course, clubs would simply split. The club pitch is vital to this being 100%; it means declarer will always know who guards the last club. Note that Bertheau’s compound squeeze line is not 100%, as declarer can guess wrong as to which suit West has unguarded.
Therefore, the club pitch by West is an error, although understandable since declarer’s hand was completely unknown. To avoid giving declarer a sure-thing line, West must first pitch a heart. A club pitch on the 4th trump would be OK, since any pitch by declarer weakens his hand in a way that kills some variant of my 100% line.