I’ve had an open issue for the last few weeks regarding why “odd” characters were showing up in Custom Property fields in my company’s Solarwinds Orion/Network Performance Monitor install. I detected them when I put a business-rules-integrity-checker in place, but I didn’t know where they came from. I cleaned up all the existing cases and waited to see if it would happen again. It did, and now I know where they came from and, I think, why.
Even after I understood the problem I couldn’t Google up any references to this situation, so I’m documenting it. One caveat – we’re running a non-current version of NPM (10.1.3; yes, we’re working on upgrading) so the issue I’m going to describe may not exist in later versions.