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One difference is that the first transaction spent a p2pkh uxto and the second one spent a p2pk. Has anyone spent a pay-to-public-key uxto with Electron Cash and did it work?
there is no "p2pk" as far as i know. there is just P2PKH which means "Pay To Pub Key Hash" which is the usual key pairs which need 1 signature (the address begins with 1).
the other thing is "p2sh" which is "Pay To Script Hash" which is those multi signatures.
and electron cash does not exactly support multisig for the time being:
https://github.com/fyookball/electrum/blob/bcc19c6e2c5e37a462bd953adb1187b2b69700b1/RELEASE-NOTES#L77-L84