Pouches should be emptied when full. If allowed to overfill, the weight of the effluent can break the seal and cause leakage. Extremely Warm Temperatures. More frequent pouch changes or a change in wafer material may be required to avoid leakage. Pouch Wear and Tear.
Disposable wafers DO wear out.
If you are stretching your wear times to a week or more, leakage may be due to the wafer wearing out. Try more frequent pouch changes. Improperly Stored Appliances. Appliances do not last forever. Ask your vendor what the recommended shelf life is for the brand of pouch you wear.