What are some potential issues you might encounter when using miscellaneous functions in PHP?

When using miscellaneous functions in PHP, some potential issues you might encounter include incorrect usage, lack of input validation, and compatibility issues. Incorrect usage of functions, such as passing incorrect arguments or using functions in inappropriate contexts, can lead to unexpected results or errors. Lack of input validation when working with user-provided data can result in security vulnerabilities or data integrity issues. Compatibility issues may arise when using certain functions that require specific PHP versions or extensions. It's important to understand the function's purpose, properly validate input, and ensure compatibility when using miscellaneous functions in PHP.