Issue with burning funds on Kusama relay chain

[rockbmb]

Is there an existing issue?

• I have searched the existing issues

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• This is not a support question.

Description of bug

On the Kusama relay chain, burning funds via balances.burn burns more than expected.

Steps to reproduce

1. Fork Kusama relay with chopsticks
2. Note the current total issuance via balances.totalIssuance(); let this number be named old

3. Using the Alice dev account, call balances.burn for 1 KSM

4. Check balances.totalIssuance() again; let this number be new

5. Verify that old - new does not equal 1 * 10^12 = 1 KSM, when it should
   • let fee = 410589072 be the fee applied
   • In fact, old - new = 82117816, which happens to be very close to floor((fee * 2) / 10) = 82117814