Searching by meta values showing inappropriate result

First of all, one never should rely on raw $_REQUEST: believe me, this is a security issue.

PHP has 2 functions: filter_input and filter_input_array that helps you to sanitize your request data.

In addition, in your request dump I don’t see any $_REQUEST['custom_bath'], but you are using that value, that can be a cause for the issue. You should check that a variable is setted before use it.

Using my suggestions your code becomes something like this

$args = array(
  'custom_textarea'   => FILTER_SANITIZE_STRING,
  'custom_price'      => FILTER_VALIDATE_INT,
  'custom_price1'     => FILTER_VALIDATE_INT,
  'custom_beds'       => FILTER_SANITIZE_STRING,
  'custom_bath'       => FILTER_SANITIZE_STRING,
  'custom_garage'     => FILTER_SANITIZE_STRING
);

$get = filter_input_array( INPUT_GET, $args, TRUE );
$post = filter_input_array( INPUT_POST, $args, TRUE );
$request = array_merge( $get, $post );

$query_args = array( 'relation' => 'OR' );

if ( ! empty( $request['custom_textarea'] ) ) {
   $query_args[] = array(
     'key' => 'custom_textarea',
     'value' => "%{$request['custom_textarea']}%", 
     'compare' => 'LIKE'
   );
}

if ( ! empty( $request['custom_price'] ) && ! empty($request['custom_price1']) ) {
   $query_args[] = array(
     'key' => 'custom_price',
     'value' => array( "{$request['custom_price']}", "{$request['custom_price1']}" ), 
     'compare' => 'BETWEEN',
     'type'    => 'SIGNED'
   );
}

if ( ! empty( $request['custom_beds'] ) ) {
   $query_args[] = array(
     'key' => 'custom_beds',
     'value' => "{$request['custom_beds']}", 
   );
}

if ( ! empty( $request['custom_bath'] ) ) {
   $query_args[] = array(
     'key' => 'custom_bath',
     'value' => "{$request['custom_bath']}", 
   );
}   

if ( ! empty( $request['custom_garage'] ) ) {
   $query_args[] = array(
     'key' => 'custom_garage',
     'value' => "{$request['custom_garage']}", 
   );
} 

$query = new WP_Query( $query_args );