Potentially adding to a growing list of complaints regarding limitations with Apple's new MacBook Pro, an aftermarket Mac accessories maker reports the notebooks might not be compatible with existing Thunderbolt 3 hardware.

Plugable, a manufacturer of docking stations, adapters and other peripherals, in a blog post this week claims Apple "design decisions" prevent Thunderbolt 3 devices running Texas Instruments controller chips from communicating with late-2016 MacBook Pro hardware.

The aftermarket parts maker discovered the deficiency during compatibility testing of its existing Thunderbolt 3 dock lineup. Specifically, a pair of Plugable's Thunderbolt 3 graphics adapters were found incompatible with a MacBook Pro without Touch Bar test bed, forcing the firm to push back launch of an upcoming docking product. Plugable's flagship TBT3-UDV dock with Power Delivery/Charging, which employs a next-generation TI controller, was found compatible with the new MacBook Pro, suggesting the limitation applies only to older TI chips.

Whether Plugable's findings are accurate is unclear, though it seems unlikely that Apple would intentionally alienate owners with early Thunderbolt 3 devices. Perhaps more plausible is Plugable implemented a chip that fails to comply with specifications adopted by standard bearer Intel.

"While we have no comment on Plugable's specific complaint, products using the newest Thunderbolt chipsets, with up-to-date drivers, will have no difficulty connecting to any 2016 MacBook Pro," Apple said in a statement to AppleInsider.

A follow-up post from Plugable notes macOS Sierra is incompatible with existing Certified Thunderbolt 3 devices released prior to November 2016. Specifically, Apple reportedly requires TI's second-generation TPS65983 chipset for full compatibility.

The revelations add to complaints about Apple's redesigned MacBook Pro lineup. After the company unveiled the laptops last week, tech pundits and a swath of consumers decried the new hardware's lack of expansion ports. In particular, some users were upset that Apple removed MacBook Pro's SD card slot, a port deemed vital for professional photographers. Others took umbrage to the lack of USB ports, as the new model requires users purchase an adapter dongle to connect and charge legacy devices — Apple's own iPhone and iPad included.

In response, Apple SVP of Worldwide Marketing Phil Schiller on Wednesday defended the company's design decisions, but admitted MacBook Pro "might not be right for everyone on day one."

As for criticism that the new MacBook Pro models lack "pro level" features, Schiller pointed to the headphone jack, saying the long-in-the-tooth I/O standard was retained to support professional audio gear. As noted by AppleInsider, however, the 3.5mm port no longer supports optical out capabilities, limiting its utility to musicians, film makers and other pro users.