Cecil, W5DXP wrote:
"Net current doesn`t flow."

I`m inclined to agree, but at first current flows with a volts to amps
ratio rqual to the Zo of the line until a reflection returns to the
connection point of the stub. Then the total phase rotation within the
stub has reached 360-degrees. The complete reflection supplies a
reflected voltage wqual to the incident voltage. There is no difference
of potential or phase to evoke current. It`s the equivalent of a very
high impedance. Almost no more current is motivated to flow, once the
steady-state condition is reached.

Alexander Wing wrote on page 29 of "Transmission Lines, Antennas, and
Wave Guides":
"Suppression of Even Harmonics.- An application of a short-circuited
quarter-wavelength line is to suppress any unwanted even harmonics in
the output of a radio transmitter. A short-circuited one-quarter
wavelength long at the desired output frequency may be connected across
the output terminals or across the antenna feeder at any point without
placing much load on the transmitter at the fundamental or desired
output frequency, since at this frequency such a section has an
impedance ideally infinite, actually about 400,000 ohms."

How much current flows into 400.000 ohms?

Best regards, Richard Harrison, KB5WZI