Is the third-party app based on PD4ML?

If so, the only theoretical explanation is that the application has misconfigured TTF embedding feature or it uses corrupted TTF fonts with spaces defined wrong way.

(Sounds strange, but it is usual for special TTF fonts, intended to display digits from 0 to 9 only)

I would also suspect a buggy version of PD4ML, but I do not remember any version with a problem like that.