I bought the FREEWELL anamorphic lens.
In my opinion it had 2 defects:
1. It could only be used in certain lighting conditions, because it could not be used together with ND filter.
2. 1.15 anamorphic vs 1.33.  

The first problem seems to be overcome because FREEWELL announced that it now produces the anamorphic lenses with INTEGRATED ND filter
in 3 versions: with ND8, with ND16 and with ND32.
Unfortunately there is no video with related tests.  

Has anyone bought?

Hello there S.T. Thank you for reaching out and for sharing these information on Anamorphic Lens you have purchased for the DJI Mavic Air 2. Just a reminder that DJI do not recommend you to use a 3rd party accessories on your DJI Mavic Air 2. There is a  possibility that these accessories will work, however, since it's not tested by DJI we cannot guaranteed the reliability of the said accessory when in use. In addition, using 3rd party accessories might cause damage or harm on your DJI Mavic Air 2 and can void the warranty as well. Thank you and fly safe always.