DateTime.fromISO() returns invalid date for (some) numbers

[codingfabi]

Describe the bug
I have a situation where I want to compare and evaluate user input. The user input can either be a date string or a number. In the resolvement function, I wanted to avert checking the variable type and just parse the input into a date and check whether this parsed date is valid. This works perfectly fine except for numbers between 10 and 24.

To Reproduce
CodeSandbox

Actual vs Expected behavior
I would expect the function to either work with arbitrary numbers or with no numbers at all. This behaviour seems inconsistent.

• Browser [e.g. Chrome 84, safari 14.0]
• Luxon version: latest

Additional context
This is more a question than a bug report to be honest. If this behaviour is intended, I am totally fine with it. However, I am primarily wondering why it only works for integers from 10 to 24. I assume/understand that is has something todo with some time offset and I would understand every number larger than 24 not working. However, it still puzzles me that single digit numbers also seem to be a problem. Is there any particular reason behind this?