Can you please let us know if you still use the Unyson framework plugin?
It is long deprecated and could cause issues like this. We recommend upgrading to the Redux framework under Jevelin (left sidebar) > Framework Upgrade. The only thing to notice is that you need to check if you still have any pages/posts built with the Unyson page builder before removing it completely.
That is strange, currently, we are not sure what exactly could cause this.
If it is possible then we can offer to log in to your website and inspect this issue further (the login information can be shared in the private information field).