Hello, I have the same config as below in three librenms instances with the same services-wrapper.py version as you mentioned. I’m also in the latest stable version 1.62.2
OK, the only difference I see is that I have 3306 which probably is interpreted as a number and you have '3306' with apostrophe symbol which probably is read as a string.
The docs show it without apostrophe:
To be honest i don’t remember if i ever added the apostrophe or if it was there from the initial installation. Config.php configuration utilizes more or less the same “format”. I removed the apostrophe and it works as expected.