Sometimes, in the world generations, it generate flowing water/lava blocks near sources, but not connected. i have only saw that in NPC villages. Sorry for my bad english, i'm brazilian.
Oh, and sorry if this is a duplicate, i searched, but didn't found nothing simillar.
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i know how to see the seed and coords. But i alredy deleted the world. anyway, see you alredy found the problem and fixed it in MC-11280 , so, yeah '-'
As usual, world seed and location would be nice (that is, before taking screenshot, enter command /seed and press F3). Those information allow using the same spot for testing. However, I think I already enough info from other cases...