php notices in log

Hi,

I’ve just had another developer look into some issues with my site and issues with plugin they develop and they mentioned they were numerous php notices in the log when they came to look at site? Screencap here of conversation: http://prntscr.com/9dy1k0 Site in question is: https://metamode.com.au/

Is this cause for concern and why would there be numerous php notices being generated? Could this be the cause of many of recent issues I’ve been experiencing with pages loading slowly?