Why are subtitles delayed on live streams on my Panasonic TV?

Connected TV | Update

*** Thursday 19 February ***

We are aware that subtitles are not in sync for live streams on some Panasonic TVs. The subtitles are appearing early. This is happening on the following device range: panasonic-tv_2018_hornet_fvp. The models are listed below.

We have been investigating this alongside Panasonic and unfortunately a solution can't be found. On demand subtitles are working on these TVs, however live subtitles won't work as expected. 

The impacted models are as follows:

TX-32FS503BTS
TX-40FS500B
TX-40FS503B
TX-32FS500B
TX-32FS503B
TX-24FS50B
TX-40FS400B
TX-32FS400B