"a common phenomenon" is correct and usable in written English. You can use it to describe situations, events, or trends that are widely experienced and widely accepted. For example: "Climate change is a common phenomenon that many people are concerned about.".
But it's actually quite a common phenomenon.
Why, then, is procrastination such a common phenomenon?
Unpeople are a common phenomenon in the media age.
Prophets were a common phenomenon in Syria-Palestine.
A common phenomenon is the Swiss-system competition divided into sections.
"It's such a common phenomenon here," Reuters quoted the school official as saying.
(This is apparently a common phenomenon; Anthony Tommasini said much the same thing in the Times).
When I feel like I can't trust my brain 100%, Ludwig really comes in handy. It makes me translate and proofread faster and my output more reliable.
Claudia Letizia
Head Translator and Proofreader @ organictranslations.eu