Cottony Texture

I made a batch of Dan Leader's Alpler Baguette a few days ago.  The crumb ended up being cottony rather than having a desirable amount of chew to it.  It offered little resistance to tearing.  I've made this bread several times before (this time, as always, in a boule shape) and I've never had this happen before.  I mixed the dough and gave it the same number of turns as before; the shaping, proofing and bake time were equally as consistent.  The only difference was that this time, the sun hit the proofing container and heated up the dough a bit.  It rose more than I normally let it, but there were none of the undesirable odors I associate with overfermentation.  My guess is that this slight amount of overproofing is what gave the bread its cottony texture.  Has anyone else ever had this problem?  Any better guesses than mine?  Also, for those who are not familiar with this particular bread, it has a small amount of a rye sourdough in it, but it is leavened primarily with commercial yeast.

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