Screenshots: http://imgur.com/a/oU4op
Textures from resource packs lower in the chain of packs seem to be able to randomly override textures higher up on the list. Depicted are screenshots of PureBDCraft overriding textures for stone and cobblestone.
Testing indicated the texture the game selects is specific to where the block is placed.
Please attach the resource pack(s) in question, a screenshot of your resource pack selection screen.
Please attach the screenshots to this ticket , not to external sites.