Given the following input:

> text in blockquote
:lazy continuation line

Running cargo run -- -e returns these events:

0..44: Start(BlockQuote(None))
2..44: Start(Paragraph)
2..20: Text(Borrowed("text in blockquote"))
20..21: SoftBreak
21..43: Text(Borrowed(":not a definition list"))
2..44: End(Paragraph)
0..44: End(BlockQuote(None))
EOF

Running cargo run -- -e --enable-definition-list changes how the lazy continuation line is parsed. My guess is the : at the start of the line makes the parser think it needs to close the preceding blockquote and paragraph.

0..21: Start(BlockQuote(None))
2..21: Start(Paragraph)
2..20: Text(Borrowed("text in blockquote"))
2..21: End(Paragraph)
0..21: End(BlockQuote(None))
21..44: Start(Paragraph)
21..43: Text(Borrowed(":not a definition list"))
21..44: End(Paragraph)
EOF