On the turbotax website, it says my refund is approved and issued, but this isn't the case on the IRS refund tracker, it still shows only received. Is this normal?

[DoninGA]

On the TurboTax Tax Home web page the dates shown for a refund are only estimates based on the IRS target of issuing a refund within 21 days after receiving the tax return.  This is a target only and not a guarantee.

Only the IRS website will have the current status of the tax refund - https://www.irs.gov/refunds

Once a tax return has been Accepted by the IRS or a State, TurboTax receives no further information concerning the tax return or the status of any tax refund.

After the tax return has been Accepted by the IRS (meaning only that they received the return) it will be in the Processing mode until the tax refund has been Approved and then an Issue Date will be available on the IRS website.
See this IRS website for federal tax refund FAQ's - https://www.irs.gov/refunds/tax-season-refund-frequently-asked-questions