data loss occurs every week

Hi All,
Can someone help me with this? Thank you!
I am using InfluxDB 1.7 OSS to store monitoring data from icinga2. My system has been running smoothly for 3 years without any issues.
However, after upgrading icinga2 to the latest version about a month ago, I have noticed that data is missing for approximately 3 consecutive days every week.
The data loss occurs at the end of the week, but the missing data spans across the middle of the week. At the time of the occurrence, I checked and found no abnormal logs

we run influxdb in a single node and all configs are using default option:
OS: CentOS Linux release 7.6.1810
InfluxDB version: 1.7.3

> show retention policies
name duration shardGroupDuration replicaN default
---- -------- ------------------ -------- -------
autogen 8760h0m0s 168h0m0s 1 true


The report provides no repository files, tests, or entry points. Start by checking the Icinga2 upgrade timeline, InfluxDB 1.7.3 logs, retention policy, and dates of the missing data; done means identifying a reproducible cause and a verified prevention or recovery path.

Written by the indexing model from the issue text.