frame-back-step stops working after a few frames (when opening smb:// url)

Important Information

Provide following Information:

• mpv version: v0.37.0-484-g665a472098 (built Debian-package with libsmbclient support manually enabled)
• Linux Distribution and Version: Xubuntu 20.04.6 (64bit)
• Source of the mpv binary: mpv-build (github)
• If known which version of mpv introduced the problem: already in v0.32.0-1ubuntu1
• Window Manager and version: X11

Reproduction steps

Open a videofile from a Samba (CIFS) share, using the "smb://" URL prefix:
$ mpv --no-config smb://guest@hostname/share/folder

1. Seek to a position far enough, so you could frame-seek backwards for at least a minute or so.

2. Now use "," to seek backwards 1 frame:
   Hold "," until the video stops rewinding

3. Now neither "," nor "." has any effect anymore. The player seems "stuck".

4. However, pressing left/right arrow keys, or seeking manually (clicking) to any other position works.

5. After this "re-seeking", frame-seeking (,.) works again.

Until seeking back again (=repeat step 2).

Expected behavior

The same as opening the same video file directly from the local filesystem:
Use frame-seeking back-and-forth without the player getting stuck.

Actual behavior

The player gets stuck, so that frame-seeking seems disabled/broken - until re-setting the player's playback position in any other way (keyboard or GUI).

Sample files

I've generated one (i-frames only to avoid GOP causing the issue), using ffmpeg:
ffmpeg -f lavfi -i testsrc=size=1920x1080 -t 300 -r 25 -pix_fmt yuv422p10le -c:v ffv1 -level 3 -an test.mkv

Start by reproducing the issue with mpv --no-config smb://guest@hostname/share/folder and the generated test.mkv, then compare frame-seeking over SMB with the same file on the local filesystem. Trace the frame-seek behavior after repeated , presses and after a manual seek. Done means backward and forward frame-seeking continues to work over SMB without requiring another seek operation.