Description:
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Maybe there is a reasoning beyond this. However, unexpected output is produced with ltrim and rtrim if the string has a palindrome-'like' structure.

Reproduce code:
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$str = 'daobcd';
echo ltrim($str, 'dao')

$str = 'daoabc';
echo ltrim($str, 'dao') /

$str = 'bcsedeo';
echo rtrim($str, 'deo');

Expected result:
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1. bcd

2. abc

3. bcse

Actual result:
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1. bcd

2. bc

3. bcs