TEKAFG3XXX: Device Front Panel slow to respond when controlled remotely

INTER have reported an issue that the front panel of their physical AFG3021 function generator is subject to extreme lag to the point of being almost unusable when the IOC is connected to it. The workaround they used is to set up everything that was needed from the front panel while the IOC was off, but we should investigate whether there is a deeper issue with the IOC process interfering with the device.

### Acceptance Criteria
- The cause of the issue is understood
- The issue is resolved, or a follow up ticket created if not an easy fix

## How to Test
_verbose instructions for reviewer to test changes
(**Add before making a PR**)_