The "IsFromMe" logic was implemented in several places in the Bitcoin
Core wallet. We had correctly updated CWallet::IsFromMe(CTransaction)
(which was used in most places in the wallet) to check for shielded
notes being spent, but did not notice that CWalletTx::IsFromMe also
needed this check.
This bug has existed since before Zcash launched. It went unnoticed
because CWalletTx::IsFromMe was previously only called from code
used to either create purely-transparent transactions, or provide
informational output on non-critical RPC methods.
Closeszcash/zcash#5325.
Jack Grigg