Posible "bug" only for beta optinn testers.. the first time i checked this option , everything was ok,winminner downloaded xmr-stark,benchmark it and start working without problem all day. Afternoon i tried installing new hardware,(changing gpu drivers) and restarting my pc. Winnminer starts full benchmark,but going in loop with last xmr benchmark,(xmr_stark was NOT in the benchmark list) after some time i found the solution , just checked out from beta testers,save setigs,checked in again,save setings and now xmr_stark showed in the list and benchmark was ok.
Sorry for my English 😀
Edit-seems to working fine now.