I understand the annoyance that this can cause and this is why I know that "it is not well seen" but personally I think that this is not so bad (except for specific characters), since I have been on the internet this has been a very common practice in fandoms of series/movies and personally I think I've gotten used to it. And with respect to the "canon" of Trolls, this franchise has also done this practice XD (just not for nsfw), the character of Harper in the first movie is shown with a very young appearance but in the series and in future renders She is shown with an older appearance, even though the time that has CANONICALLY passed between trolls and trolls WT is only one year, and between trolls WT and Trolls BT it is one month. Despite this fact, Harper is seen as an adult by the fandom and I have even seen her being shipped with John Dory.