Hm… Very strange… On iPad it works instant and smooth without killing the cache of its Safari browser.
(There are no caching things going on so far on my website btw.)
But on iPhone the issue is still available. Killing the cache in Safari makes no difference.
I assume it is an issue with Adblock Pro App / VPN or any other app are in background. Friend of mine checked this issue on his Android and it works fine.
No problem, will find a solution.