The first one was inserted in 12-packs of Pepsi soda. Thus a Food Issue. Here's the listing 1997 Upper Deck Pepsi Insert Seattle Mariners. The second one was given away (issued) by the team at their stadium during a game. Thus a Team Issue.
Yes, another confusing issue. I can see why it's so confusing when you have the cards in-hand. Especially, 10 years later. You'd assume the one with the Pepsi logo was the 12-pack insert and the one without was given away by the team. But Pepsi was a corporate sponsor for both sets. I can only assume they put their logo on the stadium giveaway so people would know they sponsored them. Whereas, the ones inside the Pepsi 12-packs were obviously sponsored by Pepsi. And if I were to make a logical assumption on the number prefix, I'd incorrectly assume the "M" stood for "Mariners" (Mariners team issue) and "P" stood for "Pepsi" (Food Issue).
I think any set name for the Team Issue won't clear up the confusion. But, I'd call the Team Issue "1997 Upper Deck Seattle Mariners Stadium Giveaway". Here's the checklist at BaseballCardpedia
Someday my cards may double in value and then be worth half of what I paid for them.