I've checked this ticket and confirmed the issue happened from lucee - 188.8.131.52-SNAPSHOT.
But, I got this error String index out of range: -1 while tested with the above example.
It works fine in ACF. I've attached the result of ACF.
Docs works again with 184.108.40.206-SNAPSHOT
I've checked this ticket with lucee version 220.127.116.11-SNAPSHOT. Yes, it works fine now.