When delegating to validators, sometimes there is a precision loss that causes an incorrect number to be displayed when querying the delegation.
It is easier to trigger this case when the values for validatorTokens and validatorDelegatorShares do not match.

Example

Validator state:

validatorTokens:          "10132421222471611505485287"
validatorDelegatorShares: "10142563785454078365766009.473933091465315992"

Delegation:

amount: "2000000000000000000"

Expected result: 2000000000000000000
Actual result: 1999999999999999999.999999999999999999

Possible cause and fixes

Option 1: Fix in Query Layer (Simpler)

Modify the delegation query to round the result to the nearest integer.

return types.NewDelegationResp(
   del.DelegatorAddress,
   del.GetValidatorAddr(),
   del.Shares,
   sdk.NewCoin(bondDenom, val.TokensFromSharesRoundUp(del.Shares).TruncateInt()),
), nil

Option 2: Refactor SharesFromTokens function

Refactor the SharesFromTokens function to use decimal division instead of integer division:

We can fix this by refactoring to Quo instead which the TokensFromShares function already uses:

func (v Validator) SharesFromTokens(amt math.Int) (math.LegacyDec, error) {
    if v.Tokens.IsZero() {
       return math.LegacyZeroDec(), ErrInsufficientShares
    }
    return v.GetDelegatorShares().MulInt(amt).Quo(math.LegacyNewDecFromInt(v.GetTokens())), nil
}