I couldn't reproduce this in D11 with alpha6 of the H5P module. I used the "Language" dropdown in the node's Edit form to change it, but both before and after saving, the h5p content remained unchanged. Is that the correct reproduction step (as opposed to other methods of changing language)?
- 🇺🇸United States sim_1
This is a few years old now and since we aren't able to reproduce I'm going to close it as outdated. If other users or OP are still having this issue feel free to re-open.