If the cursor has not shown up yet pressing enter on the remote has no effect on the "Search for Subtitles" screen but when I go back to a higher menu it seems that the enter has been recognized on the previous menu page. So yes, the focus seems to remain back on the higher menu until the cursor shows up in "Search for Subtitles".
I tried this several more times and the delay for the cursor to show up seems to average about 20 seconds. I cannot tell if scrolling or pressing enter on the remote has any affect on the delay. I am running the Emby app on an LG OLED55B6P with WebOS 3.
I also realized it may be related to the fact that I normally use a Harmony remote control which does not replicate the pointing cursor that is available on the LG remote. With the LG remote you can control the TV's on screen cursor just by pointing the remote control rather than hitting U/D/L/R scroll buttons, just like a PC mouse cursor. If I use the LG remote and place the LG cursor on a field or check box on the "Search for Subtitles" page and hit enter it highlights immediately. If I go to the page and the Emby highlight has not appeared yet and I try to used the U/D/L/R scroll buttons on the LG remote it reacts the same as for the Harmony remote which is no response until the highlight appears.
Note this was the same before installing 1.0.20 which does not seem to have had any affect.