I can reproduce it only after moving the caret from an inline editable macro (e.g. info box) to outside, or the other way around, but the floating toolbar doesn't disappear afterward if I keep the caret in the same location and only type. For some reason the floating toolbar thinks the editor has lost the focus when moving the focus between a nested editable and the main editable.
This message was sent by Atlassian Jira (v9.3.0#930000-sha1:287aeb6)
If image attachments aren't displayed, see this article.