Doesn’t have to be bias. Could just be that a higher percentage of women in engineering are here for the big money and not for the love of spending 14 hours with their head down coding. If that’s the case you would naturally expect a significantly higher percentage of them to jump on that management pay raise when offered instead of turning it down for a pay raise.
Not in anyway stating I believe this is true or is what is happening, just offering a counter point for how it could happen with no bias on anyone’s part.