Sony FE100-400mm HELP

[Ctt]

I purchased a 100-400mm FE lens back in April, have been using it for a while and love the pictures.  Just recently I noticed the lens started to make almost a grinding sound inside the housing..  then I noticed focus wasn’t working correctly... I called Sony then had me send it out to Precision Camera for repair.  I got it back and started shooting to nice images again.. then 4th time I used the lens, i am noticing the grinding sound again but this time the images are clear.  I just don’t recall hearing the noise before...  its like parts are grinding on something... anyone else run into something like this before...  I then thought maybe its coming from my A9 but then I put the lens on my a7riii and same thing..  so just wondering if this is normal or should I call sony again...  thanks

Edited September 13, 2019 by Ctt