Electricitymap-contrib: Transmission arrows wrong arranged at first startup

[Bohne13]

On Chrome for Linux an Chrome for Android the Arrows are not arranged correctly at first load.
Chrome 83 latest stable release.
If i reload the page, everything is fine!

[q--]

I've seem this in Firefox for Windows sometimes as well, not sure what causes it. Zooming in or out resolves it

[fbarl]

Thanks for reporting this @Bohne13!

This issue was most likely introduced by my map transition to React (#2395 / #2434) - I've also noticed it a few times but only when opening the debug console while the map would be loading (I guess it has to do with the viewport resizing then), so I didn't think of it as a high priority :thinking:

I'll assign myself to it though as I touched that code last so would probably figure how to fix it quickly.