Tesla beat its own previous record—and Wall Street's expectations—by delivering 95,200 cars in the second quarter of 2019. That's a big jump from the first quarter, when Tesla delivered a disappointing 63,000 vehicles. And it's modestly higher than Tesla's previous record of 90,700 vehicles delivered in the fourth quarter of 2018.

Wall Street reacted positively to the news, sending Tesla's stock price up 6 percent in after-hours trading.

Tesla reported producing a solid 87,048 vehicles in the second quarter—up from 77,100 vehicles produced in the first quarter and up slightly from 86,555 vehicles produced in Q4 2018.

In the first quarter, Tesla produced more vehicles than it delivered. This was largely because logistical problems prevented Tesla from getting many cars to customers overseas before March 31. In the second quarter, the situation reversed. Thanks in part to that backlog of undelivered vehicles, Tesla was able to deliver 8,000 more cars than it produced in Q2.

While Tesla's quarterly production and delivery numbers seem positive overall, there are still a couple of reasons for Tesla shareholders to worry.

A big concern is about the Model S and Model X. Combined production for the two models averaged about 25,000 units per quarter during 2017 and 2018. Then in the first quarter of 2019, Tesla produced a paltry 14,150 units. The second quarter numbers were only slightly better, at 14,517 units.

Some decline in these numbers was to be expected, since Tesla hasn't given either model a major overhaul in several years. Indeed, one likely reason for the reduced production is rumors of a Model S refresh later this year. Customers interested in Tesla's high-end sedan may be waiting to see the revamped model before they place orders.

Still, having shipments of Tesla's more profitable cars suddenly fall by 40 percent will be a drag on Tesla's second-quarter financial results.

Another worry is whether Tesla will hit its own vehicle production target. Since the start of the year, Tesla has said it expects to produce between 360,000 and 400,000 vehicles in 2019. Tesla produced about 164,000 vehicles in the first half of the year, so the company will need to produce almost 200,000 vehicles in the second half of 2019 to meet the goal. That seems doable, but it's not going to be easy.

Interestingly, Tesla re-affirmed its vehicle production target when it announced Q1 production figures in April. But today's Q2 production press release didn't mention it.