I'm using AEM 6.4 with SP3.

I'm currently having trouble adding components to a page and editing existing components in Touch UI.

For some reason the add component icon doesn't appear on the main parsys on the page:

Additionally, the edit component button isn't appearing either:

For some reason, I can edit the content in classic mode, so this looks like it's a Touch UI issue.

I have been using this author for around six months with no prior issues. This error occurred after a deployment this morning, which I have tried reverting with no success. The code in that deployment was fairly innocuous: just a minor change to a HTL file. I have also tried restarting the server.

I cannot see any errors in the console or in the error log.

Any thoughts on what the cause of this might be?