gifio.OnDiskGif stops displaying next_frame() if web workflow is not enabled and USB not connected to host

[RetiredWizard]

CircuitPython version

Adafruit CircuitPython 9.2.1-13-g617915ee80 on 2024-12-02; Adafruit Feather ESP32-S3 Reverse TFT with ESP32S3
Adafruit CircuitPython 9.2.1 on 2024-11-20; Adafruit MatrixPortal S3 with ESP32S3

Code/REPL

import board,displayio,gifio,time
import digitalio
led = digitalio.DigitalInOut(board.LED)
led.direction = digitalio.Direction.OUTPUT

disp = board.DISPLAY

odgcc = gifio.OnDiskGif('classic40.gif')

with odgcc as odg:
    cs = displayio.Colorspace.RGB565_SWAPPED

    facecc = displayio.TileGrid(odg.bitmap, \
        pixel_shader=displayio.ColorConverter(input_colorspace=cs))

    splash = displayio.Group()
    splash.append(facecc)
    disp.root_group = splash

    start = 0
    next_delay = -1
    # Display repeatedly.
    while True:
        while time.monotonic() >= start and next_delay > time.monotonic()-start:
            pass
        next_delay = odg.next_frame()
        #next_delay = .5
        led.value = not led.value

        start = time.monotonic()

Behavior

If there is no WiFi credentials in settings.toml and the board is not connected to a host computer via USB a couple frames of the GIF file are displayed and then the animation stops. Oddly, the LED continues to blink. Connecting a host computer to the boards USB port when the animation is frozen causes the animation to begin and disconnecting it again causes it to stop again.

Description

If I comment out the call to odg.next_frame() and replace it with a statement setting the next_delay to .5 seconds the LED blinks steadily regardless of whether the host computer is connected to the USB port or not.

Additional information

Connecting the boards USB to a powerbank results in the same behavior as when it's not connected to anything so for the animation to work a host computer must be connected (or settings.toml must enable web workflow).

classic40.zip