It was reported recently by the customers, that some CNC Tech headers made of nylon got some “bubles/blisters” and looked like they were “inflated” a little after soldering them on PCB.
Checking this issue with the manufacturer reveals that when the nylon material was changed, the soldering profile for the parts had changed as well. Datasheets were updated, and some did mention that baking of the parts is needed prior the soldering, but some datasheet did not have the baking data added.
CNC issued the document “Nylon Product Shelf-Life Statement” which is added now to the product page for all CNC nylon headers parts that DigiKey carries
To emphasize, this “blistering” phonomenon is a visual problem and does not affect part functionality