Why is Live Captioning not working after iOS 18.2 update?

Hi all. We've been using facetime with captioning for about a year. It's been pretty good for my hard of hearing mother. Of late it's not working. We've updated to oas18.2. See pics below, when we open Facetime, connect with a call, touch the 'i' icon a window opens, we select 'live captioning' and the live captioning window opens and shows us the text. problem is the text window is half hidden. when we select 'done' to close the live captioning on or off switch the live captioning window changes to a thin black rectangle which is so small we can't see the text anymore. no way we have found to make this thin black rectangle window bigger. 4 hours with Apple support screen sharing has not found a fix. Might you have any ideas?

[Re-Titled by Moderator]