That's a lot of poppies and they do seed themselves quite readily. Yes I would say they need to be thinned or you will have a lot of spindly poppies that won't do well. Do or did you have shorter poppies somewhere near where the short ones are. Could they have cross-pollinated. Was the one you had a hybrid. Maybe they reverted back to one of the original parent plant.

I would keep some of the short ones and see what you end up with. Maybe it's a new variety.

I see iris - are the 'weeds' poppies?

Poppies are perennials, right??

Weeds are gone in this pic. Yes, those are iris. The light colored 'carpet' is the poppy, and no, these are not perennial varieties. I did find 2 of the perennial variety plants at the other end of this bed (wasn't sure what they were, so I left them, and lucky I did- they were the Oriental Brilliante that I planted almost 3 years ago!), but the majority of this bed is only annual the varieties. Mostly Giganteum, and other pinks/purples/whites/reds & mixed ones.

Here's some pix of what's in here...I also have some poofy white ones, and poofy lavendar, and other forms of poofy:
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I'm no expert, but it looks to me like you planted a mix, perhaps Angel Choirs? Either way, they are lovely. Make plants to thin even more next year! What a nice problem.

Actually, the only 'mix' that I put in here was a Shirley mix, and I wasn't real fond of it. These others I purchased all individually from a gal on eBay (onestoppoppyshop). She's got a ton of nice ones, so I picked the ones I liked, and bought those.
I didn't put the Shirley seed back in after the first year. Second year the bed was 90% Giganteum and only a few of the other varieties- only because that's the only one I sprinkled last year. I really liked the Gs.

This year I sprinkled EVERYTHING I had...maybe that was my mistake. If this rain ever lets up, maybe I'll have poppies, albeit small ones. Sigh.

I'll know better next year. I'll still collect the seed, but I won't sow them; see what happens.

Not an expert but... My guess at the early attempt at flower production is perhaps stress from the overcrowding? I agree with the advice to thin thin thin! The picture you posted along with the individual flower photos of the entire bed in bloom looks like a good spacing to aim for. Remove all the ones along the edges of the wood, I would say at least 5" space around the outside edges and then space at whatever distance you think best from there. What a fantastic and beautiful variety you have!