One specific question was asked if a shard could be harmed by nightblood. Brandon responded that it could because it "Contains" a lot of investiture the fact the word contains was used indicates that it holds it other wise that wording is strange.
A further question asked why nightblood constantly needs to consume investiture. He replied that nightblood is leaky which also seems to indicate that there is some kind of storage otherwise what would it be leaking?
It also seems that someone asked what happens to nightbloods consumed investiture which was RAFO'D