Editing H5P Activities Timing Out

We recently updated from version 3.6.10 to version 3.9.3 and the new core H5P functionality is not working as expected in our production site. Whenever we try to edit an H5P activity in the Content Bank, we experience very long wait times and usually it eventually times out with a 504 error. It does, however, seem to save the changes even when it times out. This happens no matter what kind of activity we try to edit and no matter how big or small the change is - I have a very simple Accordion activity and adding one letter of text will cause this.

This does not happen in our staging environment, so we have been trying to figure out what is different between our staging and production environments that could be causing the issue. We have looked at database logs and last week we rebooted our file server, but we are still experiencing this issue. Does anyone have any ideas what could be causing this? Let me know if there is somewhere else I should direct this question. Thank you in advance!