Solid white flake or rather chip in the NPH?

There were these big white flakes in my NPH cartridge the other day. I rolled it around but the ball didn't break them up so I left the cartridge overnight and now the flakes are gone but there are small dark specks. I suspect the specks would disappear with some rolling but I switched to another cartridge in the box. The second cartridge didn't have flakes but after rolling it still had a couple of specks which I suspect would go away but I was a bit creeped out so I went to a new box ( different batch ), no flakes but a couple of specks that seem to be breaking up so I went with that cartridge. I've never seen an actual flake or specks in the insulin before, maybe I never looked carefully before, the specks aren't visible when the cartridge is in the pen. I'm not sure if I should check to see if it's smoother tomorrow or just take them back to the pharmacy, I had already used the other three cartridges in the box. I looked online to see what insulin gone bad might look like but didn't find any pics.

The flake was more like a white chip. The instructions say not to use any with snowflakes or crystals but the flake didn't look like a snowflake or crystal.

Ever seen flakes in your insulin before? What did you do?