Deceptive Site! warning?

One of my PBN sites has a "Deceptive Site!" warning from firefox and has also been deindexed by google. It was a PBN site with spun content on there. When I go to the site after ignoring the "Deceptive Site!" warning it looks exactly the same and has no bad links on it. I have a few questions.

1) Is it possible to get a "Deceptive Site!" warning for spun content?
2) Are the two matters of "Deceptive Site!" warning from firefox and being deindexed by google related?
3) Is it possible to get it re-indexed by google by updating wordpress, uninstalling plugins etc and then resubmitting it to google or should I just move on?

Might want to check that there is nothing hidden in there and that your site didn't get hacked in some way. However a shitty site with spun content isn't going to provide much value as a PBN anyway.

Yes its possible.

Could be malware infection. I have had that before on a site of mine. Check with your hosting provider to scan for malware.

Not possible for spun articles, might be something else. Check it on WOT as well as McAfee sites for some kind of warnings. You will definitely find something there.

Just move on,its just a trick that forces you to do something dangerous.
It also be produced if your browser attempts to redirect to websites known for online scams.
I think it could be a malware action on your site.