I was showing these 3 websites to a friend:
All are with xwp 3.8.1 and skylab theme and the big image in homepage was not loading with a misterious error of an old version of internet explorer. And into the error title there was the keyword: Autoptimize.
After deleting autoptimize then he was able tosee the websites correclty with internet explorer. Other browsers are ok instead.
I?m sorry but I'm not able actually to tell you the IE version and I don't know if I will be aver able.