Also, have you successfully received transactions from other sources? ie. Does Bitcoin Core shutdown when receiving any transaction... or does it only do it when you are receiving a transaction specifically from a nicehash payout? 
Just transferred from an exchange and successfully synchronized with v0.21.1 ... so the problem is always and only with Nicehash transactions in connection with v0.21.x
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e2df3a45b07736c35eb391f883d47a7ec8e1c0cec2353b251984ecc90f99c024
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