Setting opacity as transition-property causes error

[chris5marsh]

Running sublime_prefixr on a block of CSS such as:

    transition:opacity 0.4s;

Causes that line to be changed to

    opacity 0.4s;
    opacity 0.4s;
    opacity 0.4s;
    opacity 0.4s;
    opacity 0.4s;

As far as I know, it is only opacity which causes this behaviour.