If one receives an offline message when Spark is loading, there is probably a racing condition and chat window loads faster than some other elements. Actually chat window appears faster than system tray icon and the roster window loads up. So such chat window doesn't have emoticons picker and buzz button. Can be fixed by reopening a chat window, though not very convenient.
Also Translator plugin doesn't load.
Another side effect is that if you get offline messages while logging in, text in the chat window is not scrolled down to show the new message.
Я могу воспроизвести это в Spark 2.9.3