I've noticed that breadcrumbs aren't clickable while there is an active notification, I presume this is due to the notification overlaying the breadcrumbs during it's active state.

I've seen this too. I think it's been like this since 2.5 was released. Anyway, for whoever is able to make this change to the CP CSS I was able to fix that behavior with the following CSS:
#notifications-wrapper {
pointer-events: none;
}
#notifications .notification {
pointer-events: auto;
}
This still allows the text in the notification to be selected if that were important. If not then just the first rule would fix it.
And if anyone wanted to make that fix right now to any of their sites they could add the above CSS to their CP with CP CSS
Fixed for the next release. Thanks!
Most helpful comment
I've seen this too. I think it's been like this since 2.5 was released. Anyway, for whoever is able to make this change to the CP CSS I was able to fix that behavior with the following CSS:
This still allows the text in the notification to be selected if that were important. If not then just the first rule would fix it.
And if anyone wanted to make that fix right now to any of their sites they could add the above CSS to their CP with CP CSS