Tax topic 152:
This tax topic provides general information about the IRS processing of returns. If the IRS needs more information from you, they will follow up by a letter sent to you, there is no need for concern when you see this particular topic.
Please view the following for more on Tax Topic 152: https://www.irs.gov/taxtopics/tc152
The messages and bars on the Where's My Refund site change all of the time; and sometimes the same message is displayed continuously, or the bars do sometimes disappear entirely.
For more information see TurboTax FAQ: https://ttlc.intuit.com/replies/4495802