We are going to hold the meeting Monday 8AM.According to the description we are assuming that some of the contact gel was left in the bottles due to dry up effects.
As the gel consists of more than 50% of deionized water such effects are known to happen over time (especially if a gel bottle has already been opened for use).
This is also one of the limiting factors for the useful life span of the product.
Please note that Lot 2300 had expired 2015-12 (which is just about when the issue arised) and that Lot 22AB had expired 2015-11 (meaning that the gel shouldn't have been used anymore at that time).
Nevertheless we have decided to accommodate your customer by a replacement (free of charge) of the 4 gel bottles.