Infuse subtitle issues

L.S.,

I am using Plex as a media server on my iMac (OSX 10.9.4), and have connected Infuse (Pro 2.3) to Plex on my iPad Air (iOS 7.1.2). Plex contains a number of mkv video files with the corresponding srt subtitle files. However playing the mkv files on my iPad, or through my iPad on my Apple TV 3 (software version 6.2) does not show the subtitles, my first issue.

Getting subtitles through the "Get More..." command mostly works OK: subtitles are found and are displayed. The second issue is that subtitles sometimes "hang", a subtitle remains on screen far longer than it should and during that time no new subtitles are displayed.

Any help with either of the issues, especially the second issue, would be welcome.

Wil Dieteren