Light brown "shadows" in polycarb

[3Dsigns]

What are the faint brown streaks in this new polycarb? Brand new. Will it go away? Did they cook it too hot? too long?

 

[Gino]

Can you produce a picture ??

 

[3Dsigns]

They are actually closer to a dirty yellow, vertical or somewhat vertical streaks

 

[JBurton]

Seen a lot of crap show up in brand new poly sheets ever since they shut down production of white to make all that clear for covid. I had one that I refused to send out as it was 50% opaque black marked in a large area, but otherwise everything else has been just barely passing.
This looks pretty bad though. Can you illuminate it and see if they yellow shows? I'm assuming you bought the pan and didn't form it in house. Give the moulders a chance to replace it.