We were able to get our support case escalated and support came back with the following change which seems to have fixed out issue. Running this command is non-disruptive, but we chose to perform this change after hours just in case.
Run the following at the HNAS CLI prompt to change the Oplock setting:
set oplock_granular_max_grant_level 7
Run this command to verify the current setting:
set | grep oplock_granular
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If you want to remove this setting, run the following at the HNAS CLI prompt:
unset oplock_granular_max_grant_level
Run this command to verify the current setting:
set | grep oplock_granular
Hope this helps.