**Describe the bug**
A clear and concise description of what the bug is.
**To Reproduce**
A stand-alone chunk of code (with no dependences to other packages, user-land function nor variables with unknow values), for example:
```php
echo Carbon::parse('2018-06-01')->subDay()->month;
```
**Expected behavior**
A clear and concise description of what you expected to happen.
**Actual behavior**
Show the value(s) you get. If you get an error or exception, provide the whole stack trace of it.
**Versions**
- PHP: [e.g. 8.4.11] (use `echo phpversion();` to get it)
- Carbon: [e.g. 3.10.2] (run `composer show nesbot/carbon` to find it)
**Additional context**
Add any other context about the problem here. If some default timezone or other php.ini settings are in use for instance.
I am running the latest version of Carbon within Laravel.
Lately I am seeing this in my logs:
Carbon\Carbon::addUnit(): Argument #4 ($anchorDay) must be of type ?int, true given, called in /home/ss/application/vendor/nesbot/carbon/src/Carbon/Traits/Date.php on line 2973
I can't consistently reproduce it but I am seeing it.
PHP Version:
PHP 8.4.25 (cli) (built: Aug 25 2026 18:15:03) (NTS gcc x86_64)
Copyright (c) The PHP Group
Built by Remi's RPM repository <https://rpms.remirepo.net/> #StandWithUkraine #NoAI
Zend Engine v4.4.25, Copyright (c) Zend Technologies
with Zend OPcache v8.4.25, Copyright (c), by Zend Technologies
Carbon Version:
3.14.0
Thanks!
Hello, this error means your code or a dependency of your code call a Carbon method (addDays, subHours or the like) and is passing `true` instead of a number to the `$anchorDay`.
You need to inspect the rest of the stack trace from your log to see what is making this faulty call.