New bug from the new update: Whenever you return to the Beachside Cave after meeting Ditto, it plays the meeting Ditto scene again and resets your progress with them.
Solution: on line 916 (in the 0.11.2 Public version), change
<<set $StrangeNoisesAssignment to false>>
to
<<set $StrangeNoiseAssignment to false>>
by removing the extra S in the variable name.
Problem: This caused an additional bug where after first meeting Ditto, the Beachside Cave was no longer accessible at all.
Solution: on line 916 again, after the change from before, add
<<set $MetDitto to true>>
to that line, putting the game in the correct state and allowing Ditto progress.