Property manager has a conflict of interest in this – they get more fees if the rent goes up. But at the end of the day, you have the contract with the tenant, the property manager does not. So it should be up to you.
You’re probably aware of the pitfalls of not keeping up with market rent – you get further and further behind and then you realise you’re not covering your costs and it takes a massive jump to catch up (which is not really fair on the tenant, even if they have been paying under market rent for some time). So in some ways the property manager has valid reasons (beyond self-interest) to try and keep you up with market rent.
But if you want to carry that risk, that’s your decision, not the decision of the property manager, who works for you.