Looks to me like air has gotten in under the decal via the holes. Recommend using a rubber squeegee to squeeze the air/water out the best you can (short strokes toward the hole, aiming to push the air/water out the hole), then apply a decal solvent such as MicroSol or MicroSet to cause the decal to improve adhesion and conform to the surface better (which will also have the effect of pushing air out).
I don't work with waterslide decals much anymore but, when I did, I used both MicroSet and MicroSol. Both slightly soften the decal- MicroSet improves adhesion while MicroSol makes the decal conform better to irregular surfaces (which is often the case with a pedal enclosure, even if the surface irregularities aren't noticeable to the naked eye). I would apply both solutions, just to be safe.
Mike
View attachment 74114