Dryness

[Jim]

Wow! Only one gram? You must have a very precise scale to measure the loss of one gram. If the casing is separating from the meat, it indicates that the meat is shrinking/drying. You may want to check that the fridge has air circulation and dehumidification is woking.
The sausages should have firmed up in a month, especially the 32 mm. It usually takes 3 weeks max to loose 35% in a good fridge.