ENGIN-X INSTRON/ARACCESS: Missing log entries.

## Where?
Follows on from https://github.com/ISISComputingGroup/IBEX/issues/7204.

## How?
- Missing entry in continuous log. A single entry line would be missing from the continuous log but present in the full log. After the place where the missing line is supposed to be the log timestamps go out of sync. I have attached logs with this issue present (line 32):
[INSTRON_01_2022-09-08T16_56_26.txt](https://github.com/ISISComputingGroup/IBEX/files/9615294/INSTRON_01_2022-09-08T16_56_26.txt)
[INSTRON_01_2022-09-08T16_56_26_continuous.txt](https://github.com/ISISComputingGroup/IBEX/files/9615295/INSTRON_01_2022-09-08T16_56_26_continuous.txt)

## Reproducible?
Yes

### To Reproduce
- Turn on INSTRON logging.
- Generate for at least a minute.
- Stop logging.

## Acceptance criteria
- [ ] Cause of issue is understood.
- [ ] Issue fixed.

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

## Notes

The framework for some system tests has been written on [this branch](https://github.com/ISISComputingGroup/system_tests/compare/Ticket7204_fix_archiver_access_log). They do not currently generate their own log files correctly so the tests would need fixing to reproduce the issue.

Logs seem to occasionally fail to generate entirely. If you reproduce this while investigating, make another ticket for it.