Ballasted EPDM

Looks to me like a seam plate got stepped on. Don't know how. No plates anywhere.

25+ years old over ballasted .045, EPS, pre-cast concrete. Whole roof ponds. This one didn't weep, halo, puff dust, nothing. Little dollar coin sized ceiling stain.

Sometimes, they just "click". Saw this first scoop, ended up scooping a lot more to make sure this was the only issue. Confirmed saturated EPS under it when I cut it out.