Apple 2018 MacBook Pro models said to have been equipped with “membrane” that prevent debris from entering the butterfly mechanism. In an internal document distributed to Apple Authorized Service Providers, Apple seems to have confirmed the same.
Though the US version of this Service Readiness Guide does not mention anything of this sorts, it does link to a separate internal document titled “Butterfly Mechanism Keycap Replacement MacBook Pro (2018)”. This reads: “Caution The keyboard has a membrane under the keycaps to prevent debris from entering the butterfly mechanism. Be careful not to tear the membrane. A torn membrane will result in a top case replacement.”
iFixit is the first to discover the thin, silicone barrier underneath the keycaps in a teardown of the new 13-inch MacBook Pro with Touch Bar. Apple filed a patent for a contaminant-resistant MacBook keyboard back in 2016. As for Apple, it just confirmed that 2018 MacBook Pro models feature an “improved third-generation keyboard for quieter typing.”
After complaints from users, a few class action lawsuits, Apple has initiated a worldwide service program last month, offering free repairs of 2015-and-later MacBook and 2016 and 2017 MacBook Pro keyboards, that came with low-profile butterfly switch mechanisms. However, the company confirmed that third-generation keyboards will not be offered as replacements under its service program for 2016 and 2017 MacBook Pro second-generation keyboard.
Apple’s internal 2018 MacBook Pro Service Readiness Guide reads:
Keyboard and Keycaps
The keyboard has a membrane under the keycaps to prevent debris from entering the butterfly mechanism. The procedure for the space bar replacement has also changed from the previous model. Repair documentation and service videos will be available when keycap parts begin shipping.