I encounter this on a fairly regular basis - a project uses a third-party library and there is either a bug in the library that we can’t seem to avoid hitting, or there’s a feature missing or not 100% ideal for our use case.

Every reasonably sized C++ project these days will use some third party libraries. Some of them like boost are viewed as extensions of the standard libraries that no sane developer would want to be without. Then there is whatever GUI toolkit your project uses, possibly another toolkit to deal with data access, the ACE libraries, etc etc. You get the picture.