We've released hotfix (beta) versions of WPML and String Translation, mainly focused on performance issues vs WordPress 6.3.
Can you please install these versions and retry? You can either do this from Plugins -> Add New -> Commercial and switch to Beta channel and install or can directly download from your https://wpml.org/account/downloads/ account.
IMPORTANT: Take full backup of your website and database beforehand. It is highly advised to try this on a staging/dev site first, so your live website isn't compromised.