Lifespan of enzymes in oxidizing conditions about 15 to 20 minutes. That's fine for doing a wash, but not so great for shelf life or product stability.
With powder formats oxygen bleaching agent and enzymes are coated, this keeps each out of other's manor so giving decent shelf life. With liquid products obviously this can become an issue. One way is to have two separate chambers; Vanish or someone long ago had a stain remover/booster product with two bottles stuck together. Enzyme stain liquid on one side, liquid oxygen bleach on other. Miele and others with automatic dispensing systems simply keep two apart in different bottles.
Regarding liquid laundry products in general they aren't as long lasting (shelf stable) compared to powders. This may explain why job lots of unsold products are being flogged on eBay, various online auction sites and discount stores. Each month vast amounts of unsold laundry liquid, pods, etc... are taken from shelves and sold onto secondary markets.
Years ago one had to travel to find job lot stores that sold surplus products. Such places are still about but there is also online. H-Bid and other auction houses have tons of liquid and pod detergents that are shelf pulls from likes of Costco, Target and other such places.
What we consider "old" product versus say P&G or Henkel may differ. Professional take is liquid laundry products "expire" after about three to four months on shelves. They may be perfectly good or perhaps have begun to suffer some degradation in power. Scent may not be as strong in bottle and or lasting on fabrics. Cleaning power not same... Those sort of things.
Far as many European testing groups are concerned liquid laundry product formats (liquids and pods) are more polluting than powders. Just fact liquids require far more stabilizers and preservatives than powders puts them on that list. Then there is the plastic containers liquid products are sold in and or polymers that pods are made from.