Checking for MX records using checkdnsrr() function in PHP

Question

I have researched about checkdnsrr() function for checking mx records and found out that mx records for example.com does not exist but

dd(checkdnsrr("example.com", "mx"));

is giving me true statement.

I have seen the previous answers but in that most of the issues are updated but this issue remains. Please suggest some ways to validate MX records.