MyVocab anomalies

Occassionally, I run across a highlighted word whereby all but the first character is highlighted.

For example, in a message there is this text:
I think 酪(lào)=curled milk 
The ào in lào is underlined and if I click on the vocab word, up comes tào.  This is not a consistent problem, just an occasional problem.

In another message, there is this text:
天气(tiānqì) = weather
It appears to me s tiānqì with all but the t highlighted.
 

Having just posted this message, let me add that it is exhibiting the same behavior here.  In this case, all occurrences of ào are highlighted as are all occurrences of iānqì.  This is bizarre.  Of course, only I will see this since these are my vocab words.