Tamron USA officially published a press release saying that Tamron will fix the 28-75mm f/2.8 Di III RXD FE lens autofocus issue via a firmware update.
Notice about 28-75mm F/2.8 Di III RXD (Model A036) Operation
Dear Tamron product users and potential purchasers.
Thank you for your interest in Tamron products.
We would like to announce that we discovered some issues with the auto focus of our new lens, model A036FS; 28-75mm F/2.8 Di III RXD for SONY mirrorless cameras, released on May 24, 2018. The issues occur primarily when using the camera in video recording mode.
Rest assured, we are evaluating the cause of the error and for the solution to this matter. We expect this issue to be resolved very shortly and we will release a firmware update at that time.
Regarding the firmware updating process, please be assured that the process is accomplished directly through the SONY camera and supported by the Sony firmware updating function. As soon as the process is finalized, we will explain the process in detail on our website.
We sincerely apologize to all users and potential purchasers for any inconvenience this issue may cause.
Via: Tamron USA