Not sure if this question belongs here, but it is kinda a programming question.

I'm running xampp 3.2.2 (just Apache and MySQL) with php 7.1.14 on Windows 7 to work on several Symfony (2.8) applications.

Initially I had them hosted with vhosts using different ports and accessed them by <http://my-ip:port>, but that was a PITA because 1) the browser mixes up the cookies, forcing you to continually log in when switching apps and 2) some php cache (I think, its been a while) mixes up User classes, forcing you to restart Apache.

I then switched to name-based vhosts (nothing fancy, local name resolution using C:\Windows\system32\drivers\etc\hosts) which got rid of the issues.

Not sure if it is related to running several apps, but now I got a new problem: Everything started out fine, but then Symfony sporadically threw this error in my face:

```
Warning: class_implements(): Class  does not exist and could not be loaded

```

Most of the time there is no class name (note the two spaces), sometimes it says some gibberish like `\.php$`. I typed this one from memory, but I think it was a less well-formed regex. I also get other stuff that's definitely not a class name.

Over time (a few weeks), "sporadically" changed to "every few minutes/requests", even with just using one app. What helps is restarting Apache, sometimes I also need to delete the Symfony cache.

What is going on here and how can I fix it?