Graph is wrong and beyond the port speed

Why am I getting graphs beyond the port speed? It seems the daily graph is ok but graphs which are more than a day seems wrong.
All graphs were fine a few months ago.

(this graph is from a 1gbps port of a Cisco 3850 switch, but most of the ports have this issue)

The output of ./validate.php

Component | Version
--------- | -------
LibreNMS  | 24.4.1 (2024-04-20T17:56:51+03:30)
DB Schema | 2024_04_10_093513_remove_device_perf (291)
PHP       | 8.1.12
Python    | 3.6.8
Database  | MariaDB 10.5.17-MariaDB
RRDTool   | 1.7.1
SNMP      | 5.7.2

[OK]    Composer Version: 2.7.4
[OK]    Dependencies up-to-date.
[OK]    Database connection successful
[OK]    Database Schema is current
[OK]    SQL Server meets minimum requirements
[OK]    lower_case_table_names is enabled
[OK]    MySQL engine is optimal
[OK]    Database and column collations are correct
[OK]    Database schema correct
[OK]    MySQL and PHP time match
[OK]    Active pollers found
[OK]    Dispatcher Service not detected
[OK]    Locks are functional
[OK]    Python poller wrapper is polling
[OK]    Redis is unavailable
[OK]    rrdtool version ok
[OK]    Connected to rrdcached

Are you using SNMPv1? Looks like you are wrapping the counters on your device.

It is SNMPv2c and the graphs were fine a few months ago.
Also daily graph looks fine.

Perhaps the device’s snmp daemon crashed while polling and resulted in bad values. Search the docs for remove spikes if you want to clean it up.