Apparently, Fiserv’s decision to embrace CashEdge’s Popmoney brand name for its peer-to-peer payments service has its risks.

In a meeting with Fiserv officials this week, they were clearly concerned about the name, which they chose over Fiserv’s own homegrown ZashPay. When the discussion turned to the Popmoney brand, the Fiserv officials made it clear that they were not to call it “Pop,” only “Popmoney.”

To review, Fiserv purchased CashEdge last fall, giving it access to the Popmoney product and brand.

It seems there is a bit of a trademark issue with “Pop.” Indeed, Capital One Financial Corp. had the trademark for “Pop,” although that mark appears to have been abandoned in mid-2009. What is more striking is that CashEdge itself filed for the trademark for “Pop” in 2010, and that mark was granted to the company late last year (serial number 85171948).

The problem, however, appears to be a company called DPE Label Holding Corp. in Brooklyn, N.Y. DPE filed for a trademark of “pop” just a few days before CashEdge, and DPE’s application remains live (serial number 85490360).

I’m no lawyer, but it seems like DPE plays the trademark game, and that’s enough to forbid the word “pop” from Fiserv’s halls.