Issues with aggregate graph showing inaccurate data before a specific date

I’m having an issue that I’ve noticed on the aggregate graphs of our Libre instance. For some reason when looking at an aggregate graph, if I set the start date to be 4 months before the current date then the information is wildly inaccurate.
Example images:

These images are both of the same graph, in the first image, the start date is set to 4 months and 1 day before the current date (22nd May 2023). In the second image it is exactly 4 months ago.

This is only happening on aggregate graphs, if I look at the individual graphs used to make up this aggregate then it all looks fine and correct.

Is this a setting that needs changing somewhere or does anybody have a similar experience?

./validate.php output:

Component | Version
--------- | -------
LibreNMS  | 22.7.0
DB Schema | 2022_07_19_081224_plugins_unique_index (243)
PHP       | 7.3.24
Python    | 3.6.8
MySQL     | 10.5.8-MariaDB-1:10.5.8+maria~buster
RRDTool   | 1.4.8
SNMP      | 5.7.2

[OK]    Composer Version: 2.5.5
[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 schema correct
[OK]    MySQl and PHP time match
[OK]    rrdtool version ok
[OK]    Connected to rrdcached
[WARN]  Your local git contains modified files, this could prevent automatic updates.
[FAIL]  We have found some files that are owned by a different user than 'librenms', this will stop you updating automatically and / or rrd files being updated causing graphs to fail.

The custom files are weathermap files which should have no impact on a graph.

Any help appreciated.