The 26-year-old goalkeeper famously dropped two game-changing clangers in the 2018 Champions League final for Liverpool after suffering concussion.
Errors have continued to curse him throughout his time in Turkey, leading to the club deciding not to take up their option to sign him permanently this summer for around £7million.
Now the former Germany U21 stopper is allegedly blaming the floodlights at Besiktas' home ground for his mistakes.
Fotospor reports the lighting leaves him dazzled and confused.
If true, then those claims could be linked to that blow he suffered against Madrid.
The specialists that treated the ex-Mainz No1 stated that long-term sight issues were not uncommon for individuals who suffered a severe concussion.