Gravity Falls Season: 3 (Birds in a cage)

Dipper and Mabel return to Gravity falls after 5 years and everything seems to be well and good... guess some things never change, but that doesn't mean everything stays the same either. Dipper finds Grunkle Stan speaking gibberish during sleeps and has nightmares about a Giant AXOLOTL. Does this make any sense, or is this weirdness considered normal since they're in gravity falls.