Why is it difficult to peel off white Direct to Film (DTF) ?

Why is it difficult to peel off white Direct to Film (DTF) ? Sometimes using the same DTF film, it is good to peel off. why is it difficult for you to peel off ? and it often gets torn. What is the reason? Maybe the hot stamping temperature is wrong....

Haiyi DTf film

Haiyi DTf film The surface of the film is dry and clean, and can be easily peeled in the hot, cold and warm conditions. Major advantages: The pattern after ironing is like the texture of PU glue, the tensile resilience is strong and does not deform, and the feel is softer than...