Translators are expected to edit the initial translation, but the system showing the warnings for a paragraph is often acting too early. As captured in recent user research: "Alerts/warnings in Content Translation are not always well-understood and timing of their presentation is critical."
One issue is that the current system shows warnings for a paragraph when the input focus is lost. This was intended to capture the moment where the user is done with one paragraph and starts the next one, however this may happen while still editing the paragraph ( when adding a link, looking for a word in another tab, etc.). A more reliable approach may be needed (e.g., checking a paragraph when the focus enters a different one).
In addition, a related issue (T263116) makes things worse since users editing the paragraph further don't see the percentage of MT to go down in the process or the warning to disappear.
The video below shows the issue for a translation of Nasothek from English to Greek where adding a link results in the warning being shown for the initial text paragraph without giving the user much chance to improve the initial translaiton before the warning is shown: