Component Values Not Updating

I have an SMTP query to send to / from particular addresses that are selected from a select component. This works fine for one of my apps, and was working with this particular app until recently. What I am finding now though, is the value of my select component is not updating, so the email is sent out with no FROM address.

When editing the app, I can see this happening. In the SMTP query, I go into the FROM field which shows {{ select1.value }} and by default is NULL. I then go into the select and choose the email to send FROM. When going back to the box in the query it still shows NULL. I can then click on another query and go back to the SMTP query where it has updated the value to the correct email address.

This is also happening with a multi select component in exactly the same way.

I use exactly the same method on another app which appears to be working fine. It is using the same SMTP details, and JS Join query to put the multi select addresses in the correct format. I would explore the Join Query in more if it wasn't for the fact a simple select component value is also displaying the same behaviour.

Anyone experienced this or have any suggestions. TIA.