Contradiction with Jeremiah 50:39
Isaiah 23:15 mentions Tyre will be forgotten for seventy years, while Jeremiah 50:39 speaks of Babylon never being inhabited, suggesting a permanent desolation.
Jeremiah 50:39: Therefore the wild beasts of the desert with the wild beasts of the islands shall dwell [there], and the owls shall dwell therein: and it shall be no more inhabited for ever; neither shall it be dwelt in from generation to generation.
Contradiction with Isaiah 13:20
Isaiah 23:15 implies a temporary period of forgetting Tyre, whereas Isaiah 13:20 states Babylon will never be lived in again, indicating an eternal desolation.
Isaiah 13:20: It shall never be inhabited, neither shall it be dwelt in from generation to generation: neither shall the Arabian pitch tent there; neither shall the shepherds make their fold there.