vf remove will cause the mpv to freeze

[verygoodlee]

Important Information

• mpv version shinchiro's build 20231101
• Windows Version Win11 23H2

Reproduction steps

vf append with label, then remove it by label
for example input.conf

a vf append @test:vapoursynth="~~/vs/test.vpy"
b vf remove @test

vf append works properly，vf remove will cause the mpv to freeze，
then you can only use the taskmanager to kill the mpv process

on 20231030 before version do not have this problem