Shipping a kit to my MFG. ECCN code questions for exporting goods

Hello, I am trying to ship a parts kit to my MFG but I think some may be a problem. Some like the STM32 (which is manufactured in China anyways) has an ECCN code of 3A991A2 and some are listed as 3A991A1.
Will customs seize these items even though the COO is China and I am just trying to send them to my MFG to be soldered on circuit boards? How do I remedy this?

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