I've just checked my listings and can't quite understand bidder's actions.
I have an item listed with a start price of £10. It received a bid today from an ebayer with 1000+ fb.
Within a couple of hours it received a bid from another bidder with less than 50 fb and took the price up to £34.98 with bidder no1 still in the lead. At this point it was showing as 2 bidders, 3 bids (I'm on the app so don't know who has made multiple bids).
I've just checked it now and the price has gone back down to £22.?? with bidder no2 winning.
It looks like bidder no1 has reduced their highest bid to put no2 in the lead...ie like I've rigged it to push the price up.
Why would someone do that?! 
Btw, it still has 3 days left with plenty of watchers so I'm hoping for a few other bids yet but I'm just a bit unsure what's happened and why.