Going to the previous page right after changing chapters will put you on the last page of the previous chapter, but will still show the first page of

[Speedphoenix]

on the last page of a chapter, go to the next page, you will ed up on the first page of the next chapter
then quickly go to the previous page, the reader will properly be in the previous chapter, but sometimes the displayed image will still be the first page of the new chapter (instead of last page of previous capter)