This was reported as a Clojure bug. jank has the same behavior.

• Slack: https://clojurians.slack.com/archives/C06E3HYPR/p1764848613250419
• Ask: https://ask.clojure.org/index.php/14798/leading-zeros-in-numbers

000000000000042 ;; => 34 (octal) 000000000000042M ;; => 42M (decimal)

We'll need to see the behavior which Clojure chooses to identify how we should fix it.