V1.18.1 (0375576)
Apache/2
MySQL version: 10.6.18
PHP version: 8.1.19
In a random que: Search field gives no results when I search for a (serial)number that only consists of numbers. For example: 20445802.
The number exists in an active custom field, as you can see in the que.
As soon as a letter is added in a random place: for example: 2044B5802, the ticket is shown in the search results.
I have made a few screenshots.

search input only numbers

search results only numbers nothing found)
Test 2:

search input with letter

search results with letter (results shown)
It is important that we can find the serial numbers with the search function, even those that consist only of numbers.
Is this a known issue?
How can I fix this?