Previous we found success in resolving our issue by disabling auditing of gateway events (scripted tag writes) by setting 'Security > General > Gateway Audit Profile' to '-None-'. That allowed us to continue auditing project events.
However, we have noted a bug in v8.1.42 which is adding gateway scoped tag write events to the audit log despite the Gateway audit profile being set to -None-.
Changes to the 'Security > General > Gateway Audit Profile' had no effect on resolving the issue. We found that disabling 'Enable Auditing' setting in Project settings did stop the auditing of gateway scoped tag writes but that should not be the case as tag/gateway scripts are not project dependent. Also we do want to audit actual project events.
We examined another Ignition server running v8.1.41 and noted it did not exhibit the same behavior, then we upgraded it to v8.1.42 and it started exhibiting the same erroneous behavior.
Submitting a bug report as a support ticket (#120383).