Hello!
“When Myrddin turns into a chibi the second time”
Oh no…
There should only be one section where he turns into that, and after he turns back, he should remain normal. Was he normal first and then suddenly turned into chibi again?
In case I am misunderstanding, and he did not actually turn from normal to chibi again, then to proceed, you would need to complete the other interactions too, such as talk, fact, and joke.