On mobile devices pull-to-refresh is enabled.
This leads to a reload of the page e.g. if you swipe over left panel.
Fortunately the route is kept, because it is stored in the url, but the overlay is gone 
Therefore I suggest to disable pull-to-fresh.
For example: In CSS body { overscroll-behavior: none; }
Could you describe the issue with pull to refresh? That is a designated behavior?
I am not sure if I fully understand the question …
Pull to refresh: Pull-to-refresh - Wikipedia
This feature means a functionality: If you scroll down an element, which is already scrolled down to bottom, the browser reloads the page. As far as I understand this feature has been introduced for social media.
But it is discussed very controversial - searching for an option to disable it in browser, I found a lot of emotional (from my point of view often even hateful) posts blaming google for that feature - a severe topic is that loss of data entered in a form due to unintended refresh happens quite often.
As far as I could see, there is no option to disable that in browser settings - it is only possible to disable that by website, eg. by CSS setting.
I run into that issue when I tried to find out further information about
Buttons "Add as Start/Destination/ViaPoint/ShapingPoint" in speech bubble of overlay waypoints - #5 by rumbrummer
I tried to scroll down left panel - but the panel could not be scrolled down, so browser reloaded the site and overlay was gone.
I dot not know how many trouble this “feature” causes, but from my point of view it is complete useless - so I would prefer to switch it off.
Did my answer help, or did I misunderstand the question?
Thanks for the explanation. Yes this helps indeed.
It can be very problematic to change the default behaviour of browsers as this breaks user expectation. I think most people know pull-to-refresh and would wonder why it doesn’t work. So I am not sure we should do this.