I have been running performance checks during the morning and tried with other browsers, used the debugging tools. I can see why it could be slow but I definitely need more trials to understand where it comes from. Bear with us while we're on it :)
and as i said earlier, this is really helpful for us to know so thank you
The commenter was actually very considerate and raised a warning where it might be seen. And they were kind enough to attempt this with two different browsers. After that you can buy my troubleshooting time at its usual hourly rate.
(Because it's a frequent enough issue: I wouldn't see that warning as being about a one-off obscure bug that will affect few people and doesn't matter. It's a warning that the web site probably did not enough take compatibility in consideration - and was approved without such consideration.)
"Runs fine for me" is an absurd bar for reliability / compatibility, no?
Not to say I dismiss the comment, definitely looking at it cause it might come from somewhere else. Just that I yet don't see what is the bottleneck.