Display issue

Hello,
I’m using JP 5.1
I’m having a display issue that was isolated after trial and error to JP.
The display of pages, forum and blog is sluggish.
It starts with the theme layout and its color and some widgets.
After 1-3 seconds the text is display, like “fill in the blanks”.
I’ve disabled JP and the problem is gone and all fine – all is displayed in one shot.
Enabling JP causes the problem again.
[Note – I did not update to 5.2 because the editor issue, I had to roll back to 5.1]
You can look at my site to see the visual effect that I was trying to explain here:
https://mityaalim.org/
Thank you