WinHTTP error 12175 after days and huge number of requests

I use the Windows WinHTTP library to make http and https requests and sometimes get WinHTTP error 12175, usually after a few days of work (sometimes weeks), a hundred thousand to millions of requests.

If this happens, the only way to "fix" the error is to restart the service, and sometimes the errors will not go away until Windows (server) restarts.

Interestingly, this error appears "gradually": getting some of them for some HTTPS requests, then after a while the service receives them for 100% of https requests, and then they pop up even for normal HTTP requests (the service makes a lot of http requests and https, on the order of tens per second, for many servers). HTTP connections are made directly, without any proxies. OS - Windows 2012 R2.

AFAICT there is no memory leak or corruption, outside of 12175 errors, the rest of the service is working fine, has no access rights or suspicious exceptions, the service usually responds to requests, etc.

I have a suspicion that this could be due to Windows Update doing OS certificate updates, credential updates or something like that, but I could never confirm this.

Has anyone else observed this behavior? Any workarounds?