I assume you mean the liners are sticking to the muffin after baking. Then ripping off chunks of the muffin when you try to remove the liner to eat the muffin. That’s pretty common with the quality of liners available to home bakers. Look for a good quality grease proof liner. Or skip the liner and use a Wilton’s baking spray to coat the pan. You can also make baker’s grease equal parts by weight of flour, vegetable oil, and shortening. You make up a little batch and stored in an sterilized airtight jar in the refrigerator it’ll keep for 3 - 6 months. Just don’t contaminate the jar. Scoop out what you need each use. Apply to your tins, pans with a pastry brush.
Wilton Bake Easy Non Stick spray has a mix of oil and flour. There are other baking sprays, but Wilton’s is the best IMO. Look for in it any big box store that stocks cake decorating supplies like a Michael’s. Walmart, McCalls. Or speciality cake decorating supply shop. Baker’s Joy is another spray, but the nozzle does not spray as fine a mist. And I do not think the spray is as good.
Regular sprays don’t work as well for baked goods since they do not have flour in the spray.
Greaseproof liners are hard to come by and are more expensive. You will have to either order them online or buy in a speciality cake decorating supply shop or restaurant supply store.
Muffins are often eaten warm, so ... I spray my wrappers lightly. Our cupcakes, on the other hand, cool completely before eating, as we want to frost this gives the cake time to shrink & loosen it's grip on the wrapper.