I use 5.4.009 on my boxes (Duo 4K and Ultimo 4K).

The subtitles behave badly on some movie channels (C More HD),
they seem to appear irregularly, and in some cases they just
flash so you do not have time to read.

I do not know if this is due to Openvix or the broadcast.
(I have notified this to Canal Digital / Telenorsat).

I recorded parts of the movies and when I play it, the subtitles work perfectly!

What do you think about this?