Question fro HVAC experts

[Andreas W.]

In my condo I have a Goodman stud mounted air handler installed. It is 2 years old. In Summer I notice that the HVAC filter is wet. Is that from back dripping condensate leaving the cooling coils? Is that intended design, or could there be something going on funky? 

It is this one with built in filter rack

http://www.goodmanmfg.com/pdfviewer.aspx?pdfurl=docs/librariesprovider6/default-document-library/ss-gawuf107a350022fa6258827eff0a00754798.pdf?sfvrsn=0