Compose plus apostrophe doesn't work with Cyrillic

I used to have a custom .XCompose, I removed it to possibly eliminate the cause. Unfortunately, the problem persists - I can't create an accented Cyrillic character, such as the ones here [1]. Simply nothing happens when I press compose, apostrophe, а. I know it did work some (long) time ago, but I can't recall anything that could be the reason.

[1] http://ift.tt/1xHX5fK