Apparently, Google had been pressuring Acer to call off the event for awhile, as this wasn’t the first phone that launched with the supposedly forked Android OS. Also of note here, apparently Acer (as an OHA signatory) agreed not to market/implement an Android fork that is not Android-compatible. SO, there’s that. Not a surprise then that Acer’s attempt to launch an Aliyun smartphone didn’t sit too well with Google and that it would try to enforce this agreement.
Of course, at the root of this is the compatibility issue, and whether or not Aliyun is an offender to begin with — whether or not it’s actually a forked Android OS at all. To that point, Aliyun claims that its OS is built from the ground up and is Linux-based, so it’s technically not part of the Android ecosystem. Meaning, then, that it wouldn’t be beholden to dealing with OHA regulations/requirements.