Looking at my SNES, you trademarked Secret of Mana over 2 decades ago, way to go morons.
That's the copyright. Trademarks need to constantly be renewed.
I'm going to conceed, however, that the recent SoM remake counts as trademark renewal, so doing another renewal now may seem strange. However, I don't work at SE, so what would I know about how they handle trademark periods.
The alternative, is that the trademark is for the original, and somehow the remake doesn't count for that version of the game in terms of trademark. THe last time the original SoM could have a trademark renewal was in 2014 with its mobile port. So by this point, in 2019, that's enough time to need a trademark renewal. Again, if the 3D remake doesn't count for the 2D version as well.
Though again, I'm not a lawyer to know how these things work in full detail.