After updating to the latest firmware, subtitles do not appear in videos

After updating to the latest firmware, subtitles do not appear in videos.

When I connect my iPhone 13 pro Max with Xreal Beam and play it through a media player, the video and sound are fine, but no subtitles are displayed.

In previous firmware, there were some missing subtitles, but in the latest firmware, there are no subtitles at all.

[Tested media players].
Infuse
nPlayer Plus
Plex

[subtilte ext & Encoding]
srt, smi
UTF-8

Hi, in order to locate the issue, could you please tell me the iOS version of your iPhone? Also, please confirm if you used wired connection or wireless connection. Thanks in advance.