The problem with ethanol in aviation fuel is separation.

Ethanol in gasoline works fine, so long as the materials in your fuel
system and engine are made to tollerate it. But we treat avgas and
automobile gas very differently. Auto gas rarely sits for weeks
undisturbed, and fuel filler caps don't point up.

If even a small amount of water gets in to a blended gasoline, it mixes
with the ethanol and causes it fall out of suspension in the gas. It
then form a water/ethanol layer on the bottom of the tank, that may or
may not be burnable. It certainly won't burn the same way the gas
would.

In that condition, with a separate water/alcohol layer on the bottom, I
can't imaging the fuel sensors would read normally.

Once the alcohol falls out, the rest of the gas may be burnable, but
it's octane is significantly lowered. The ethanol is used as an
anti-knock agent. So you may get detonation problems. The fuel
chemists I've talked with say the raw feed stock gas (before the
Ethonol is added) is in the range of 84-86 octane.