Sometimes I get graphics issues while and after booting (Clover text only etc. pp.)

Hey everyone,

sometimes I get graphics issues. The first thing whats different in theses situations is, that clover boots in an text only mode. So instead of the icons it only prompts a text selection for the different boot options. And when MacOS boots it's only on a little area in the middle of the screen and it's flickering. After reboot everything goes back to normal. Any suggestions?