The industry standard is EPDM over a wood composite under-layment over wood or aluminum rafters and stringers with boxed openings for vents, skylights, A/C, etc. I don't know for sure what the new FunFinder roofs are, but, I suspect they are the same (my old '08 210WBS was). It (EPDM) has been around for ages and is very reliable and cost effective. Life expectancy is 10-20 years with most lasting even longer with proper maintenance and care.
As for the raised edge you have...would I be concerned? Yep.
There are thickness variances in the composite (whether chipboard or plywood), but, those thickness variances are usually measured on the order of a 32nd of an inch, not in 8ths of an inch... I would be concerned that the under-layment is not attached to a stringer or rafter, but, floating in the air or that there has already been a water incursion and the under-layment is warped or swollen. Even on new trailers, it isn't unusual to have a small, localized "bubble" in the EPDM, that's the nature of the beast and is not a cause for alarm, however, that large a raised edge in the under-layment would give rise to concern for me. I'd have it looked at while it is still under warranty. If they say that it is a "variance in thickness", get it in writing as such and that they'll be responsible in the future for hidden damage if it in fact was caused by water incursion.
And, yes, I know what the top my trailer looks like
I go up there in the spring and in the fall (waking her up and putting her to bed) and periodically during the season for other reasons. The roof is the only thing protecting the contents from the "great outdoors", just as in your sticks and bricks. The roof, protrusions (plastic degrades over time and becomes brittle and cracks) and the sealant should all be inspected at least annually, preferably more often.