Following an earlier report stating weakening demand for Apple’s (AAPL) iPad forced a big manufacturing slowdown at Apple’s panel supplier, more bad news emerges from China. According to data released by TrendForce, a China-based market research firm plugged into the supply chain in the Far East, display panel shipments for tablets grew 25.6% to 19 million units in December. The growth could be a positive note for the tablet market as a whole, but it comes alongside more troubling news for market leader Apple: According to TrendForce, fourth-quarter iPad sales were weaker than expected.

“The tablet shipment showed dramatic growth,” TrendForce noted in its report. “As Apple’s 9.7” product saw lower-than-expected sales in Q4’12, the inconsistency emerged between panel suppliers’ output and clients’ procurement. But Apple increased procurement significantly at the end of the year on concern of maintaining the following relationship with suppliers, resulting in a noticeable 25.6% growth in the overall tablet panel shipment MoM to 19.34 million units, but Apple‘s act must drag down the 9.7” product demand even more in Q1’13.”

Apple’s iPad mini undoubtedly impacted sales of the company’s full-size tablet, but Apple’s orders for December certainly would have accounted for the inevitable cannibalization of its 9.7-inch tablet. As such, TrendForce’s note that sales were weaker than expected could weigh heavy as Apple prepares to report its holiday-quarter results next week.

The firm also stated that LCD TV panel shipments declined 10.3% sequentially to 19.82 million units in December and notebook panel shipments dropped 10.7% month-over-month.