I find the marketing names for bamboo to be confusing, but I am assuming this is Fargesia murieliae. This bamboo is hardy to about -20C, which means that is the temperature at which it will die if exposed for more than a day or two. Damage to the foliage and culms occurs above those temperatures, and the plants are even more vulnerable if they are in pots rather than in the ground. I think what you are seeing is carryover damage that wasn't immediately apparent after the cold snap. The issues with aphids, etc., did not cause this. They still look healthy to me despite the damaged leaves. Continue to treat them normally and well watered and you should see new leaf tips forming in several weeks. The main issue is what you will do to prevent this next winter. Are you able to bring them inside in a cold snap?
Q