Once the IRS accepts your return, all refund updates are taken over by them. Therefore, we can't say for certain why your return is still processing.
The IRS generally issues refunds within 21 days. If it's been more than 21 days, we suggest calling the IRS to inquire about your refund. Go here for tips on reaching a live IRS agent when you call.
Refer to the following TurboTax FAQ for other tax situations that can delay refunds: What if my IRS refund is taking longer than 21 day ...