I did mention the commit in question, I can now confirm reading the code that Kamailio is doing DNS NAPTR resolution on IP addresses, this was not intended but the desired improvement.
``` commit 28049aafc8dd06c160ce5e7b8d5e4fc728441b0c Author: Semen Darienko semen.darienko@wildix.com Date: Sun May 3 12:26:45 2020 +0200
core: dns - use all NAPTR records
- enable using of all NAPTR records instead of the first one ordered by priority - GH #2290 ```