Please check if "Remember and Repeat" option has been accidentally switched on in the settings menu
What is Remember and Repeat?
When switched to "on", Remember and Repeat replicates the standard classroom spelling strategy Read Cover Write Check. A student types a word, it disappears and they immediately type it again from memory, benefitting from the extra repetition.
It is recommended that this feature is used when a student reaches words that they are finding particularly difficult to spell.