Staking precision/rounding anomaly

[julianrubino]

Describe the Bug Intermittent precision/rounding anomaly when staking via the precompile. Occasionally, staking an exact integer amount (e.g., 10 ZETA) results in the delegation being recorded as 9.999999999999999999 ZETA, followed by an automatic creation of a separate delegation for the residual 0.000000000000000001 ZETA after undelegation.

To Reproduce

Stake exactly 10 ZETA through the staking precompile.

Observe the resulting delegation amount.

If the recorded delegation shows 9.999999999999999999 ZETA, undelegate the full displayed amount.

Observe that a new delegation appears for the remainder 0.000000000000000001 ZETA.

This one works:

cast send 0x0000000000000000000000000000000000000800 \
  "delegate(address,string,uint256)" \
  0x4955a3F38ff86ae92A914445099caa8eA2B9bA32 \
  "zetavaloper15ruj2tc76pnj9xtw64utktee7cc7w6vzeegzu5" \
  1000000000000000000 \
  --rpc-url https://zetachain-athens-evm.blockpi.network/v1/rpc/public \
  --private-key $PRIVATE_KEY \
  --value 1000000000000000000

This one reproduced the issue:

cast send 0x0000000000000000000000000000000000000800 \
  "delegate(address,string,uint256)" \
  0x4955a3F38ff86ae92A914445099caa8eA2B9bA32 \
  "zetavaloper15ruj2tc76pnj9xtw64utktee7cc7w6vzeegzu5" \
  300000000000000000 \
  --rpc-url https://zetachain-athens-evm.blockpi.network/v1/rpc/public \
  --private-key $PRIVATE_KEY \
  --value 300000000000000000

https://zetachain-athens.blockpi.network/lcd/v1/public/cosmos/staking/v1beta1/delegations/zeta1f9268uu0lp4wj253g3zsn892363tnw3jlvjfx3

Notes:

Behavior is intermittent: sometimes the stake is recorded as the exact integer (10 ZETA), other times it’s off by 1e-18.

The stake transaction input is exactly 10 ZETA in all cases.

Expected Behavior

Staking an integer amount (e.g., 10 ZETA) should consistently result in an exact 10 ZETA delegation with no residual “dust.”

Undelegating the full staked amount should not leave a leftover micro-fractional delegation.

Actual Behavior

Sometimes 10 ZETA → 9.999999999999999999 ZETA recorded.

When undelegating that amount, a new delegation appears for the remaining 0.000000000000000001 ZETA.

Screenshots

Environment (please complete the following information):

OS: macOS

Version used:

• Binary: v34.1.0
• Cast
• Precompile: 0x0000000000000000000000000000000000000800

Wallet/SDK: zetacored and Hub

[lumtis]

Updating the PR title as it is not linked to the precompile

[lumtis]

Issue was already existing (currently on mainnet), and happen when staking to a validator that was previously jailed

[kingpinXD]

We can track this issue on the sdk https://github.com/cosmos/cosmos-sdk/issues/25263

older issue shared by stefan for reference https://github.com/cosmos/gaia/issues/1229