I'm also seeing this issue intermittently (restarting Apache resolves).
My setup is:
- Windows 7 Pro SP1 64-bit
- CI 3.1.5
- PHP 7.1.8 (also seen using 7.1.2, as well as 5.6)
- Apache 2.4.25 (stand-alone, not WAMP or XAMPP)
- MariaDB 10.1.4
Settings:
- opcache is disabled
- have seen using both file and database sessions driver
Super frustrating issue. At the moment, I'm locked into a Windows environment. Any ideas or suggestions? Thanks in advance.