🪲 Second teacher can't (always) open levels?

[Felienne]

Describe the bug
Today we ran into the issue that a second teacher couldn't open a level, he tried it a bunch of times but it did not stick (despite seeing the popup "customization saved". I am the first teacher of the class, and for me it worked right away (class id: 2003976384a84343b856976cddc011a5)

[LegoPink]

I ran into this as well, but I'm the first teacher of the class.
When I Open a level, the UI tells me I succesfully made a personalisation. But when I try the preview, the level is not always open; If I try repeatedly, it sometimes works.

The list in the 'Open levels screen show what I want to have open, even after a reload of the page or after Log out, log in (in the same browser tab and in a new tab).
But the Preview of what kids will see, can be something else.

Very annoying.