Just got a new Mazda3. Washing it for the first time. I'm getting water to bubble inside the light assemblies around the edges. My son in law thinks it's a problem that could be signs it might leak in the future. Says it shouldn't be doing it. It is happening in all the light in the rear.

Any ideas if this is a real problem, or nothing to worry about?

 

Id say it's a problem, you will probably get condensation there too - corroding the reflector and just looking bad. What year is it? I know some people on ebay sell replacements, or their OEM ones when they upgrade, so have a look there, they are fairly easy to replace.