On which exact version of PMS / Plex Web are you?
As for #1: from what I’ve seen, the theme will fade out as part of the transition to the new page – this usually takes 1-2 sec
I have not yet seen any background images getting stuck.
As for #2: there’s a feature suggestion addressing that.
As for #3: did you by chance enable the experimental universal continue watching feature on your account? This will result in on-deck and continue watching to be merged in a single hub.
Account Settings > Experimental Features > Enable early access to experimental features still under development=checked
