Short Plenum Run Question

[scary_penguin@xxxxxxxxxxx]

I just finished running network lines as part of a basement finishing
product.  I bought non-plenum cable, because I wasn't planning on
running any cable inside the air ducts, but just realized that I
actually did end up running cable across the bottom of my cold air
return vent.

Basically, the cold air return is two studs wide, so there are two runs
of 15" cable or so at the bottom of the cold air return, about two
inches below the grate that lets air into the return.

I will be amazed if the inspector even asks about plenum vs. non-plenum
cable, but is there anything I need to do for family safety?  It's too
late to run metal conduit, but I could wrap the cable in some kind of
insulation and tape it.  Thanks