DIAGNOSIS The coating is degrading, usually from using metal utensils, abrasive scrubbers, or high-heat cooking with no oil on certain foods (like marinated meats with sugar). Once it starts flaking, it won't stop.
FIX You need to replace the basket. Instant Pot sells official replacement baskets and trays for the Vortex Plus 6QT model. Stop using the flaking one immediately. For the new one, only use nylon, wood, or silicone utensils. Hand-wash with a soft sponge and mild detergent.
IF THAT DIDN'T WORK If the replacement also fails quickly, check your cleaning routine. Let the basket cool completely before washing. Never use the "clean" cycle on a dishwasher, even though it's labeled dishwasher-safe. Hand-washing drastically extends the coating's life.
HEADS UP Flaking non-stick coating should not be ingested. While one-time small flake ingestion isn't an acute emergency, consistently cooking with a damaged basket means you're eating coating particles. It's a consumable part that will eventually need replacing.