Just curious... Seems to me I read somewhere that extra coax between
antenna and radio should not be managed in a coil. Any truth to this? If
so, what's the issue?

I've got an attic antenna about 20 feet or so from an ICOM R8500 connected
with 50 feet of RG6-U. This leaves about 30 I keep coiled and wire tied on
the floor.

The only issue is that if the diameter of the coil is too small the
interconductor will cut through the insulation and short to the shield over
a period of time. If you coil it with an inside diameter of a foot or more
then you will be fine.