I was observing the TRDVOL_1 / ACVOL_1 fields for ANHJ.J on 2021-03-29 and saw that at a few times during the day, trades came in that never seemed to be reflected in ACVOL_1. I was keeping a running tally of total TRDVOL_1 and comparing to ACVOL_1. Naturally, they deviate as trades are reported, but, usually ACVOL_1 catches up quickly. However, at 08:16:20 (CDT), a trade of size 230 comes through and we never see ACVOL_1 catch up after that. It is off by 230 until another similar event at 08:58:04 (CDT) which further adds to the discrepancy.
Did I miss a correction event or is something else going on?