Unable to find constructor for several H5P content types

On one of our customer systems, opening an H5P Dialog Card activity results in a blank page. The following error is shown in the developer console:

"Unable to find constructor for: H5P.DialogCards 1.8"

This also happens for some other content types. They all show up as installed under "Site Administration->H5P->Manage H5P Content Types". We tried clearing all caches but it didn't resolve the problem. For some reason, the javascript files in the server's HTTP responses don't contain constructors for some of the content types, even though they are installed.

I can't reproduce this on other systems, but I also don't know what else to try than clearing the cache. Deleting and reinstalling the content types isn't an option as that would mean losing all the corresponding contents on the system, if I understand correctly.