Hi Stephen

I was unable to replicate the issue you're having, and we do not offer support on the plugin, but I'm sure the lovely people at H5P would be able to offer help in their community https://h5p.org/forum.

Are you able to upload a test file and edit that at all? There's one in my Google Drive you could try.

https://drive.google.com/file/d/1ff5200WIN2rUG7iIorWA5qehE8unxPc1/view?usp=sharing

A few customers have 'disable consistent cleaning' in the security settings ticked to allow H5P to perform better, but there are risks explained in the info there.

There is an updated version of the H5P plugin on the horizon, so keep your eye on the product roadmap.

Sorry I can't be more help, but the H5P community are a friendly bunch