Hi there,
I assume this is when editing in WP-Admin, rather than in the WordPress.com interface via Jetpack, correct? Using the block editor, or the classic editor plugin?
First thing to check is whether it might be a conflict with another plugin or the theme on your site – the recent update in Jetpack could have introduced a conflict with another plugin that didn’t exist before, or an update to a plugin could have introduced a conflict with Jetpack.
Please attempt to disable all plugins except Jetpack, and switch to the default Twenty Nineteen theme. If the problem goes away, enable them one by one to identify the source of the problem.
If you are able to install plugins, install Health Check. On the troubleshooting tab, you can click the button to disable all plugins and change the theme for you, while you’re still logged in, without affecting normal visitors to your site.
It would also be helpful if you can share your site’s URL so we can check it from our end. If you’re not willing to share it publicly, please open a support ticket at https://jetpack.com/contact-support/?rel=support so we can help you there instead.