[EE] Help with understanding microcontroller markings

Hi folks!

At work, we have an old design using the P89LPC936F chip (by NXP).  They
are no longer made, and we're buying old lots and using them.

But we have 3 batches of chips, and 2 of them won't program.  They are New
Old Stock, still in their reels.  I've tried look at the NXP documentation,
but haven't found anythings to tell me what the additional lines of marking
mean.

The first batch is marked
P89LPC936F
CR6028  01
TnD1343A

The second batch is marked
P89LPC936F
CKA897  02
TnD1546A

The third batch is marked
P89LPC936F
CM9073  03
TuD1644A

Only the "CKA897  02" chips will program.  Any idea of what the 2nd and 3rd
lines are?
Date codes?  Batch codes?  Or...?

Also, while trying to find documentation on the chip markings, I found that
alibaba.com seems to have vendors selling these chips (though not from NXP).
https://www.alibaba.com/showroom/p89lpc936f.html
https://www.alibaba.com/product-detail/Support-BOM-Quotation-MARK-P89LPC936F-TSSOP28_1601651848661.html
https://www.alibaba.com/product-detail/New-and-Original-In-Stock-P89LPC936F_1601671412800.html

Any comments on alibaba.com or these vendors?

Thanks!
   Bill