Firefox with uBlock Origin slow on some sites - eviltoast

I’m using Firefox with uBlock Origin on both android and windows. I’m finding more and more sites that are very slow to load, or won’t load at all. Yet when I open them in Chrome they work fine. I’m assuming the sites are just failing because of the privacy protection features of ff+ubo, and I’m happy enough to just avoid these shitty sites in general. But - I’m just checking to see - is this expected behaviour, might I have configuration issues?